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Kerala State Syllabus 10th Standard Hindi Solutions Unit 4 Chapter 2 दिशाहीन दिशा (यात्रावृत्त)

दिशाहीन दिशा Text Book Questions and Answers

दिशाहीन दिशा विश्लेषणात्मक प्रश्न

Hsslive Guru 10th Hindi Kerala Syllabus  प्रश्ना 1.
घर में चलते समय मन में यात्रा की कोई बनी हुई रूप-रेखा नहीं थी।” – लेखक के इस कथन के आधार पर बताएँ कि किसी यात्रा पर जान से पहले यात्रा की रूप-रेखा बनाना ज़रूरी है?

उत्तर:
किसी यात्रा पर जाने से पहले यात्रा की रूपरेखा बनाना ज़रूरी है। यात्रा तो हम नई जगहों को पहचानने के लिए करते हैं। रूपरेखा बनाने से जगहों की सही जानकारी मिलती है. मसंदीदार जगह बड़ी चाव देख सकते हैं और अन्य जगह छोड भी सकते हैं। हम अपने समय का सही इस्तेमाल भी कर सकते हैं।

Hss Guru 10 Hindi Kerala Syllabus  प्रश्ना 2.
घने शहर की छोटी-सी तंग गली में पैदा हुए लेखक को कन्याकुमारी के विशाल समुद्र-तट के प्रति आत्मीयता का अनुभव होने का आधार क्या हो सकता है?

उत्तर:
नुभवहीन बातों पर ज़्यादा रुचि रखना स्वाभाविक है। विपरीत के प्रति आकर्षण होना स्वाभाविक ही है। किसी तंग गली में जन्म लेने से कन्याकुमारी के विशाल तट में अपनापन का भाव जागृत होगा।

Hss Live Guru 10th Hindi Kerala Syllabus प्रश्ना 3.
‘मगर बात करने की जगह उसने मेरा बिस्तर लपेटकर खिड़की से बाहर फेंक दिया और खुद : मेरा सूटकेस लिए नीचे उतर गया।’ अविनाश के इस आचरण से मोहन राकेश और अविनाश के बीच की मित्रता का क्या अंदाज़ा मिल जाता है?

उत्तर:
मोहन राकेश का एक दिली दोस्त है अविनाश। जब चाहे वह मोहन राकेश के साथ कोई भी आचरण कर सकता है। कुछ भी करने को उसके लिए स्वतंत्रता है। प्रस्तुत आचरण से उनके बीच का धनिष्ठ संबंध का परिचय मिलता है

10th Class Hindi Notes Kerala Syllabus प्रश्ना 4.
‘मगर आप चाहे तो चंद गज़लें तरन्नुम के साथ अर्ज कर सकता हूँ।’ इस कथन से आम जनता के साथ गज़लों के रिश्ते का क्या परिचय मिलता है?

उत्तर:
आम जनता गज़लों से खूब परिचित थे। गज़ल आम जनता की ही कविता है। वे उसे गाते रहते हैं। क्योंकि उतनी मार्मिकता उसमें है। इसलिए बूढ़ा मल्लाह अब्दुल जब्बार भी शायर गालिब से परिचित थे। गायक न होते हुए भी मल्लाह कुछ गज़लें पेश करने को तैयार भी हुआ।

10th Hindi Notes Kerala Syllabus प्रश्ना 5.
‘उसके खामोश हो जाने से सारा वातावरण ही बदल गया।’ – इससे आपने क्या समझा?


उत्तर:
बूढ़ा मल्लाह झूम-झूमकर गज़ल गा रहा था। लेखक और मित्र भी उसके गायन में विलीन हो गए। उसका गला काफ़ी अच्छा था, सुनाने का अंदाज़ा भी शायराना था। गाते समय रात, सर्दी, नाव का हिलना इन सबका अनुभव नहीं हो रहा था। अब होने लगा। झील का विस्तार भी उतनी देर के लिए सिमट गया था, अब खुल गया।

दिशाहीन दिशा Text Book Activities & Answers

Hsslive Guru Hindi 10 Kerala Syllabus प्रश्ना 1.
संबंध पहचाने, सही मिलान करें।

उत्तर:

Hsslive 10th Hindi Kerala Syllabus प्रश्ना 2.
पढ़ें, यात्रावृत्त के आधार पर उचित वाक्यों पर सही का निशान ✓ लगाएँ।


उत्तर:

Kerala Syllabus 10th Standard Hindi Notes प्रश्ना 3.
भोपाल ताल में अब्दुल जब्बार और अविनाश के साथ की सैर मोहन राकेश के लिए मज़ेदार थी। वे अपने अविस्मरणीय अनुभव दफ्तर के एक मित्र से बाँटना चाहते हैं। भोपाल ताल की सैर के अनुभवों का ज़िक्र करते हुए मित्र के नाम मोहन राकेश का पत्र लिखें।

उत्तर:
भोपाल,
30-12-1952
प्रिय जयप्रकाशजी,
आप कैसे हैं? दफ़्तर में सब कुशल है न? कुछ बातें आपसे बाँटना चाहता हूँ। सोचा कि एक चिट्ठी लिखू। अब मैं भोपाल में हूँ। मुंबई के रास्ते में था। डिब्बे में सोने के लिए सीट भी मिली थी। लेकिन रात आई तो मैं भोपाल ताल की एक नाव में लेटा बुढ़े मल्लाह अब्दुल जब्बार से गज़लें सुन रहा था।

भोपाल स्टेशन पर मित्र अविनाश ने मुझसे मिलने आया था। बात करने की जगह उसने मेरा बिस्तर लपेटकर खिड़की से बाहर फेंक दिया और खुद मेरा सूटकेस लिए हुए नीचे उतरा। रात ग्यारह बजे के बाद हम लोग घूमने निकले। जब भोपाल ताल के पास आया तो मन लगा कि नाव लेकर कुछ देर तक झील की सैर करें। अचानक अविनाश ने कहा कि कितना अच्छा होता अगर इस वक्त हम में से कोई कुछ गा सकता। हमारी नाव का मल्लाह अब्दुल जब्बार गायक तो नहीं, मगर उसने कुछ गज़लें तरन्नम के साथ पेश किया। उसका गला अच्छा था। सुनाने का अंदाज़ भी शायराना था। एक के बाद दूसरी फिर तीसरी। हम दोनों उसके गायन में विलीन हो गए थे। जब वह खामोश हो गया तो वातावरण ही बदल गया। रात, सर्दी का नाव का हिलना सबका अनुभव पहले नहीं हो रहा था, अब होने लगा। फिर उससे गालिब की गज़लें सुनाया गया। भोपाल-ताल की सैर मज़ेदार था, दिल को छूनेवाली थी। दफ्तर में सबको मेरा नमस्कार कहना। बाकी सब अगले पत्र में। तुरंत ही जवाबी पत्र की प्रतीक्षा करते हुए।

Hss Live Guru Hindi 10 Kerala Syllabus प्रश्ना 4.
पश्चिमी-तट की यात्रा निश्चय ही अवाच्य अनुभूति प्रदान करेगी। गोआ काफ़ी सुंदर जगह है। वहाँ की विशेषताओं को ध्यान में रखकर एक विवरणिका (ब्रॉशर) तैयार करें।

उत्तर:

Kerala Syllabus 10th Standard Hindi Guide प्रश्ना 5.
चरित्र पर टिप्पणी लिखें।
बूढ़े मल्लाह ने एक गज़ल छेड़ दी। उसका गला काफ़ी अच्छा था और सुनाने का अंदाज़ | भी शायराना था। काफ़ी देर चप्पुओं को छोड़े वह झूम-झूमकर गज़लें सुनाता रहा।
‘दिशाहीन दिशाट के अब्दुल जब्बार का व्यक्तित्व बड़ा प्रभावशाली है। ये संकेत पढ़ें और अब्दुल जब्बार के चरित्र पर टिप्पणी लिखें।
1. गरीब
2. परिश्रमी .
3. खुशमिज़ाज .
4. सादा जीवन बितानेवाला
5. विनयशील .
6. गज़ल गायक

उत्तर:
गज़ल गायक – अब्दुलजब्बार
मोहनराकेश का यात्राविवरण ‘दिशाहीन दिशा’ के एक प्रभावशाली व्यक्ति है बूढ़ा मल्लाह श्री अब्दुल जब्बार । भोपाल-ताल की सैर में लेखक और मित्र का उनका परिचय होता है। हमेशा खुशमिज़ाज दिखाई पडनेवाला और सादा जीवन बितानेवाला था। दाढ़ी के ही नहीं छाति के भी बाल सफेद हो चुके थे। सर्दी के मौसम में भि सिर्फ तहमद लगाए आया था। भोपाल-ताल का नाविक अब्दुलजब्बार रात -दिन मेहनत करता रहता है। जब वह चप्पू चलाने लगता तो उसकी मांसपेशियाँ इस तरह हिलती जैसे उनमें फौलाद भरा हो । जब अविनाश गाने का आग्रह प्रकट किया तो बिना हिचक के तीन गज़लें छेड देता है। उसका गला काफ़ी अच्छा था। गज़लों से वह इतना परिचित था कि सुनाने का अंदाज़ भी शायराना था। कभी कभी नाव खोते समय चप्पुओं को छाड़े झूम-झूमकर गज़लें सुनाता था। असल में जब उसने गज़ले समाप्त की, वातावरण ही बदल गया था। अविनाश के अनुसार गालिब की चीज़ पेश करने को कहता है, तुरंत ही बिना एतराज के विनय के साथ गज़लें गाने लगा। मोटे तौर पर वह खुशमिज़ाज, विनयशील गरीब गज़लगायक अब्दुल जब्बार लेखक और मित्र के लिए उस रात अविस्मरणीय पात्र रहा।

10th Standard Hindi Kerala Syllabus प्रश्ना 6.
इंन शब्दों पर ध्यान दें :

इनके मूल शब्दों को पहचानें और परिवर्तन के कारण पर चर्च करें।

उत्तर:
मुझे — मैं
हमने — हम
उसमें — वह
उसकी — वह
इनका — ये
मुझसे — मैं
उसने — वह
किसका — कौन
मैं, हम, वह, ये, कौन आदि हिंदी के सर्वनाम है।
इन सर्वनाम के साथ कुछ प्रत्य लगाने से उपयुक्त शब्द मिलता है। इन्हें सर्वनाम का रूपांतरण कहते हैं। उदाहरण के लिए ‘मैं’ के साथ ‘को’ प्रत्यय लगाने से ‘मुझे’ या ‘मुझको’ शब्द मिलता है। मैं, हम, तू, तुम, आप, यह, ये, वह,वे, जो, कौन, कोई आदि हिंदी के सर्वनाम हैं।

Hindi Notes 10th Class Kerala Syllabus  प्रश्ना 7.
नमूने के अनुसार वाक्यों को बदलकर लिखें, अर्थ-भेद भी समझें।


उत्तर:

Standard 10 Hindi Kerala Syllabus प्रश्ना 8.
मान लें आप दिसंबर की छुट्टियों में दिल्ली जा रहे हैं। इसके लिए क्या-क्या पूर्व तैयारियाँ करेंगे। इस चार्ट की पूर्ति करें।

उत्तर:

दिशाहीन दिशा Additional Questions and Answers

10th Standard Hindi Meaning Kerala Syllabus प्रश्ना 1.
‘तीसरी गज़ल सुनकर वह खामोश हो गया। उसके खामोश हो जाने से सारा वातावरण ही बदल गया।’ बूढ़े मल्लाह अब्दुल जब्बार के साथ हुई भोपाल-ताल की सैर के बारे में लेखक अपनी डायरी में कुछ लिखते है। वह डायरी तैयार करें।

26 दिसंबर 1952.
कल जो भोपाल- ताल की यात्रा करने का मन हुआ वह अविस्मरणीय रहा। रात साढ़े ग्यारह बजे मैं अविनाश के साथ भोपाल-ताल पर यात्रा की। हमारा मल्लाह अब्दुलजब्बार नामक एक बूढ़ा था। वह बहुत खुशमिज़ाज नज़र आया। अविनाश के आग्रह प्रकट करते ही उसने तीन गज़लें छेड़ दी। वाह ! हम उसपर विलीन हो गए थे। रात, सर्दी एवं नाव के हिलने का अंदाज़ा पहले नहीं हुआ था। झील का विस्तार भी गाते समय सिमट गया था। उसका गला काफ़ी अच्छा था। सुनाने का अंदाज़ भी शायराना था। नाव चलाने का बीच काफ़ी देर चप्पुओं को छोडे वह झूम -झूमकर गज़लें सुनाता रहा। तेज़ गर्मी में भी बेचारा सिर्फ एक तहमद लगाए बैठा था। जब वह चप्पू चलाने लगता तो उसकी मांसपेशियाँ इस तरह हिल्ती जैसे उनमें फौलाद भरा हो। मैं और अविनाश उसके गज़ल गायन में इतना विलीन हो गए थे कि लौट जाने की बात ही नहीं सोचा था। आगे उसने गालिब की गज़ल पैश की – “मुद्दत हुई है यार को मेहमाँ किए हुए……”! आहा! क्या बात है! यह दुनीया ही कुछ और है।

Hsslive Hindi 10th Kerala Syllabus प्रश्ना 2.
रात को ग्यारह के बाद हम घूमने निकले। भोपाल ताल के पास पहूँचे तो मन हो आया कि नाव लेकर कुछ देर झील की सैर की जाए। प्रस्तुत घटना को लेकर पटकथा का एक दृश्य लिखें।
दृश्य।:

दृश्य का विवरणः
(भोपाल ताल में नाव खोते हुए एक बूढ़ा मल्लाह नज़र आ रहा है। नाव में मोहनराकेश और मित्र अविनाश है। मोहनराकेश लेटे हुए है। मल्लाह सिर्फ तहमद पहना हुआ है। कडी सर्दी है। अविनाश गज़ल गाने का आग्रह प्रकट करता है। बूढ़ा मल्लाह गाने की धुन में है)

मोहनराकेश : बडी सुहानी रात है, कडी सर्द भी है।
अविनाश : हाँ, अगर हममें से कोई इस वक्त कोई गाना पेश करें तो कितना अच्छा होता।
अब्दुलजब्बार : मैं गा तो नहीं सकता, हुजूर ।
अविनाश : फिर भी कुछ प्रयास करें।
अब्दुलजब्बार : कुछ गज़लें तरन्नुम के साथ पेश करने का प्रयास करूँ?
मोहनराकेश
और अविनाश : (एकसाथ) ज़रूर, ज़रूर ।
(बूढा मल्लाह ताल- लय के साथ गज़लें गाने लगता है।)

दिशाहीन दिशा Summary in Malayalam and Translation

दिशाहीन दिशा शब्दार्थ

Kerala SSLC Class 10 Hindi Solutions

Students can Download Basic Science Chapter 12 Why Classification? Questions and Answers, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 8th Standard Basic Science Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 12 Why Classification? in Malayalam

Why Classification? Text Book Questions and Answers

Students can Download Chemistry Part 2 Chapter 3 The World of Carbon Questions and Answers, Summary, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 9th Standard Chemistry Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

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You can Download Periodic Table Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Chemistry Solutions Part 1 Chapter 4 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Chemistry Solutions Chapter 4 Periodic Table

Periodic Table Textual Questions and Answers

Earlier Attempts for Classification of Elements

Kerala Syllabus 9th Standard Chemistry Notes Chapter 4 Question 1.
Explain the earlier attempt of classification by Lavoiser?
Answer:
Antoine Lavoisier classified the known elements into metals and nonmetals. But he was not able to duly classify metalloids.

9th Class Chemistry Periodic Table Kerala Syllabus Question 2.
Explain Newland’s law of octaves?
Answer:
Newlands arranged elements in the increasing order of atomic mass. He noticed that every eighth element has properties similar to those of the first elements. But this peculiarity could be noticed in elements upto calcium only.

Octaves of Newlands

9th Class Chemistry 4th Chapter Kerala Syllabus Question 3.
Define Mendeleev’s periodic law?
Answer:
In 1869 Mendeleev arranged the known 63 elements in horizontal and vertical columns and gave shape to the periodic table. He found that the chemical and physical properties of elements repeat at a regular intervals when they were arranged in the increasing order of atomic masses. Based on this Mendeleev proposed the periodic law of elements. The law states that physical and chemical properties of elements are periodic function of their atomic masses.

Chemistry Notes For Class 9 Periodic Table Kerala Syllabus Question 4.
What is meant by groups and periods in the periodic table?
Answer:
The vertical columns in the periodic table are known as groups and the horizontal rows are called periods.

Kerala Syllabus 9th Standard Chemistry Notes Question 5.
Evaluate the Mendeleev’s periodic table and find the following.
a) Total number of periods
b) Total number of Groups
c) Are the same elements showing similar properties arranged in the same group or same period?
Answer:
a) 6
b) 8
c) Same group

Class 9 Chemistry Notes Kerala Syllabus Question 6.
Advantages of Mendeleev’s periodic table?
Answer:
1. For the first time elements were comprehensively classified in such a way that elements of similar properties were placed in the same group. This has made the study of chemistry easy.
2. When the classification was made in such a way that the elements of similar properties came in the same group. It was noticed that certain their proper group. The reason for this was wrongly determined atomic masses and consequently, those wrong atomic masses were corrected.
Eg. The atomic mass of beryllium was known to be 14. Mendeleev reassessed it as a and assigned beryllium a proper place.
3. Columns were left vacant for elements which were not known at the time and their properties were predicted also. This gives an impetus to experiments in chemistry.

Ex Mendeleev give names Eka aluminum and Eka silicon to those elements which were to come below aluminum and silicon respectively in the periodic table and predicted their properties. Later when these elements gallium and germanium were discovered the prediction of Mendeleev turned out to be true.

Hsslive Guru 9th Chemistry Kerala Syllabus Question 7.
Explain the limitation of Mendeleev’s Periodic table?
Answer:
1. Elements with large difference in properties were included in the same group.
eg. Hard metal like copper [Cu], Silver [Ag] were included along with soft metals like sodium [Na] potassium [K],
2. No proper position could be given to element hy¬drogen. Non-metallic hydrogen was placed along with metals like sodium [Na] and potassium [K]
3. The increasing order of atomic mass was not strictly followed throughout.
eg. Co and Ni, Te and I
4. As isotopes are atoms of same element having different atomic masses, they should have been given different position while arranging them in the order of atomic mass. But this was not done.

Counting Atomic Calculator is a free online tool that displays the atomic mass for the given chemical formula.

Modern Period Table

Periodic Table 9th Class Pdf Kerala Syllabus Question 8.
State and explain modern periodic table and mod-ern periodic law?
Answer:
In 1913 Mosely through his x-ray diffraction experiments proved that the properties of elements depended on the atomic number not on the atomic mass.

According to this the periodic law of Mendeleev and the periodic table were modified consequently the modern periodic table was prepared by arranging elements in the increasing order of atomic number. The modern periodic law states that the physical and chemical properties of elements are periodic function of their atomic number.

Periodic Table Chapter Class 9 Kerala Syllabus Question 9.
How many periods in the modern periodic table?
Answer:
7

Labour India Class 9 Chemistry Kerala Syllabus Question 10.
Which is the shortest period?
Answer:
I period

9th Class Chemistry Chapter 4 Kerala Syllabus Question 11.
Number of elements in the third period?
Answer:
8

Class 9 Chemistry Periodic Table Kerala Syllabus Question 12.
Total number of groups?
Answer:
18

Periodic Table In 9th Class Kerala Syllabus Question 13.
Explain representative elements?
Answer:
Elements of group 1 and 2 also those in groups of 13 – 18 are called representative elements it belongs to metals, nonmetals, and metalloids.

Periodic Table Chemistry Class 9 Kerala Syllabus Question 14.
Do in representative elements do they include metalloids [eg. Si, Ge, As, Sb…) exhibiting the characteristics of metals and non-metals?
Answer:
Yes

Periodic Table Notes Pdf Class 9 Kerala Syllabus Question 15.
As there elements existing in solid, liquid and gaseous state find examples?
Answer:

• In solid-state- sodium, aluminum, carbon
• In liquid state – Bromine
• In gaseous state – oxygen, neon, argon

9th Class Chemistry Chapter 4 Notes Kerala Syllabus Question 16.
Write the electronic configuration of elements with atomic number 1-10
Answer:

The atom of the elements of these group show the periodically in electron filling they contain 1 -8 electron in their outermost shell. The elements of these groups are called representative elements.

Noble Gases

Kerala Syllabus 9th Standard Notes Chemistry Question 17.
List the elements in group 18
Answer:
Helium, Neon, Argon, Krypton, Xenon, Radon

9 Class Chemistry Chapter 4 Kerala Syllabus Question 18.
Now try to write their electronic configuration
Answer:
₂He – 2
₁₀Ne – 2, 8
₁₈Ar – 2, 8, 8
₃₆Kr – 2, 8, 18, 8
₅₄Xe – 2, 8, 18, 18, 8
₈₆Rn – 2, 8, 18, 32, 18, 8

Question 19.
How many electrons are there in the outermost shell of each element?
Answer:
8

Question 20.
The elements do not normally take part in chemical reactions. Find the reason?
Answer:
They have a stable configuration in the outermost shell.

Transition Elements

Question 21.
Which group of elements belong to transition elements?
Answer:
Elements of group 3-12 in the periodic table are transition elements.

Question 22.
Find out whether elements familiar to you are present in these groups?
Answer:
Copper, silver, gold, iron

Question 23.
Aren’t transition elements metals?
Answer:
Yes

Question 24.
What are the characteristics of transition elements?
1. They from coloured compound,
2. They show similarity in properties as well as in a period.
3. In compounds, they exhibit different oxidation state
eg. Fe²⁺ and Fe³⁺

Lanthanides and Actinoids

Question 25.
Which element is next to lanthanum with atomic number 57 of group 6 in the periodic table?
Answer:
Cerium with atomic No. 58

Question 26.
Find out the position allotted to the elements with atomic number 58-71?
Answer;
Separate position at the bottom of the periodic table.

Question 27.
Is the same way aren’t the elements with atomic number 90 to 103 of period 7 give separate positions at the bottom of the periodic table?
Answer:
Yes. These elements are called inner transition elements.

Question 28.
What is meant by inner transition elements?
Answer:
Inner transition elements from Cerium [Ce] to Lutecium [Lu] of period 6 are called lanthanides. Inner transition elements from Thorium (Th] to Lewrencium [Lr] of period 7 are called actinoids. Lanthanoids are also called rare earth. Actinoids are man-made artificial elements (except thorium and uranium).

Periodic trends in the periodic table

Question 29.
Electronic configuration of group I elements of the periodic table are given
Answer:

Question 30.
What is the peculiarity seen in the electronic configuration of the outer most shell of these elements?
Answer:
All these elements we can see one electron in the outermost shell.
Hence elements of group I exhibit similarity in chemical properties.

Question 31.
Which are the electrons shows the chemical properties of elements?
Answer:
Outermost electrons.

Question 32.
Is there any relationship between the group number and the number of electrons present in the outermost shell? What is it?
Answer:
Same, group number equal tot he number of election in the outermost shell for the elements in groups 1 and 2.

Question 33.
Observe figure the electronic configuration of the second-period elements of the group from 13-18 given below.

(i) Won’t we get the group number of these elements by adding 10 to the number of elements by adding 10 to the number of electrons in the outermost shell?
Answer:
Yes

(ii) Analyze table 3.1 and find whether there is any relation between the number of shells in an atom and the number of periods?
Answer:
Number of shells in an atom and the period number is same.

Size of an Atom in Group

Question 34.
Are you familiar with the Bohr model of an atom? See the Bohr model of atoms of certain elements, in group I.

(i) Which among them is the biggest?
Answer:
Potassium (K)

(ii) Which one is the smallest?
Answer:
Hydrogen [H]

(iii) What happens to the size of an atom when we move down the group?
Answer:
Increases

(iv) What is the reason for this?
Answer:
Number of shells increases.
As we move from top to bottom of a group in the periodic table the size of the atom increases as there is an increase in the number of shells.

Atomic Size in Period

See (Fig 3.3) the representation of Bohr model of elements with atomic numbers 3 to 9 in the second period of the periodic table.

Question 35.
Is there are in the number of shells with the increase in atomic number?
Answer:
No.

Question 36.
What happens to the nuclear charge with increase in atomic number?
Answer:
On moving from left to right in a period, as nuclear charge increases, the force of attraction on the outer-most electrons increases and consequently the size of atom decreases.

Ionisation Energy

Question 37.
You have understood how sodium chloride is formed by combining sodium and chlorine atoms. The Bohr model of sodium and chlorine are given below
Answer:

(i) Which among these atoms lose electrons?
Answer:
Sodium atom

(ii) Which one gains electrons
Answer:
Chlorine atom

Question 38.
How the ions are formed?
Answer:
Atom becomes charged when there is transfer of electrons [Lose or gain electrons] they are called ions.

Question 39.
Define ionization energy?
Answer:
The amount of energy required to liberate the most loosely bound electrons from the outermost shell of an isolated gaseous atom of an element is called ionization energy.

Question 40.
What are the factors affecting the ionization energy? Nuclear charge
Answer:
Size of the atom

Question 41.
When the size of an atom increases, does the attraction of the nucleus on the outermost electron increase or decrease?
Answer:
Decrease

Question 42.
Then what is the change in ionization energy?
Answer:
As the size of atom increases ionization energy decreases.

Question 43.
Can you find out how ionization energy changes as we move from top to bottom in a group?
Answer:
Ionization energy decreases.

Question 44.
What is the general trend in the variation of ionization energy on moving across a period from left to right?
Answer:
Ionization energy increases

Question 45.
Find how ionization energy changes with increase in nuclear charge?
Answer:
On moving from left to right in a period, as nuclear charge increases, the size of the atom decrease hence ionization energy increase.

Question 46.
Define electronegativity?
Answer:
In the case of two atoms joined by a covalent bond, electronegativity is the ability of each atom to attract the bonded electrons.

Question 47.
How size of an atom influence the electronegativity?
Answer:
As the size of an atom increases the distance between the nucleus and the outermost electron increases, hence the electronegativity decreases. As we move in the same period form left to right size of atom decrease hence electronegativity increases.

Question 48.
What is the basis for the chemical properties of metals and non-metals?
Answer:
Metals are the elements which give away the electrons and those that accept electrons are generally non-metals. Metals are electropositive elements because they lose electrons to form positive ions. Non-metals are called electronegative elements because they gain electrons in chemical reactions to form negative ions.

Question 49.
What is relationship between metallic character and the size of an atom?
Answer:
As the size of the atom increases metallic character also increases.

Question 50.
How do the metallic character and nonmetallic character vary while moving from left to right in a period? Arriving at a conclusion by assessing the size of atom?
Answer:
In the periodic table, while moving from to top to bottom in groups metallic character generally in-creases while non-metallic character decreases.
In a period as we move form left to right metallic character generally decreases while non-metallic character increases.

Question 51.
Don’t you think that there is a relationship between ionization energy and metallic -non-metallic character? Is the element with highest ionization energy metallic or non-metallic?
Answer;
Non-metallic

Question 52.
Then what about those having the low ionization energy?
Answer:
Metals

Question 53.
Isn’t there a relationship between electronegativity and metallic, non-metallic character? Explain the relationship?
Answer:
Non-metals are more electronegative.

Metalloids

Question 54.
Explain metalloids?
Answer:
Elements exhibiting the properties of both metal as well as nonmetal are called metalloids, eg. Silicon [Si], germanium [Ge] Arsenic [As], Antimony [Sb] and Tellurium [Te] belongs to this category.

Question 55.
You must understand certain periodic trends in the periodic table? Based on these (✓)the correct option given below in table 3.7.

Answer:

Let Us Assess

Question 1.
The table given below lists the contributions and names of scientists who made earlier attempts in the classification of elements. Fill in the blanks.

Answer:

Question 2.
Complete the table
Answer:

Question 3.
Symbols of certain elements are given. Write their electronic configuration and find the period and group in which they are included.

Answer:
a) \(_{6}^{12} C\)
Electronic configuration 2, 4
Period – 2
Group – 14
b) \(_{12}^{24} \mathrm{Mg}\)
Electronic configuration 2,8,2
Period-3
Group – 2
c) \(_{17}^{35} \mathrm{Cl}\)
Electronic configuration 2,8,3
Period – 3
Group – 17
d) \(_{13}^{27} \mathrm{Al}\)
Electronic configuration 2,8,3
Period – 3
Group – 13
e) \(\begin{array}{l}{20} \\ {10}\end{array} \mathrm{Ne}\)
Electronic configuration 2,8
Period – 2
Group -18

Question 4.
There are three shells in the atom of element ‘X’, 6 electrons are present in its outermost shell.
a) Write the electronic configuration of the element.
b) What is its atomic number?
c) In which period does this element belong?
d) In which group is this element included?
e) Write the name and symbol of this element.
f) To which family of element does is this element belong to?
g) Draw and illustrate the Bohr atom model of this element.
Answer:
a) 2, 8, 6
b) 16
c) 3
d) 16
e) Sulphur, ‘S’
f) Oxygen family

Question 5.
Electronic configurations of elements P, Q, R, and S are given below. (These are not actual symbols).
P – 2, 2
Q -2, 8, 2
R – 2, 8, 5
S – 2, 8
a) Which among these elements are included in the same period?
b) Which are those included in the same group?
c) Which among them is a noble gas?
d) To which group and period does the element R belong?
Answer;
a) P and S, Q and R – belongs to same period
b) P and Q, belongs to same group
c) S
d) R belongs to 3rd period and 15th group

Question 6.
An incomplete form of the periodic table is given below. Write answers to the questions connecting the position of elements in it.

a) Which is the element with the biggest atom in group 1?
b) Which is the element having very lowest ionization energy in group 1?
c) Which element has the smallest atom in period 2?
d) Which among them are transition elements?
e) Which of the elements L and M has the lowest electronegativity?
f) Among B and I which has higher metallic character?
g) Which among these are included in the halogen family?
h) Which is the element that resembles E the most in its properties?
Answer:
a) D
b) D
c) M
d) G, H
e) L
f) B
g) M, N
h) F

Periodic Table Model Questions and Answers

Question 1.
Symbols of certain elements are given write down the electronic configuration and find the period and group in which they are included.

Answer:
a) \(\begin{array}{l}{23} \\ {11}\end{array} \mathrm{Na}\)
Electron configuration 2, 8, 1
Period – 3
Group – 1
b) \(_{17}^{35} \mathrm{Cl}\)
Electron configuration -2, 8, 7
Period – 3
Group-17
c) \(_{9}^{19} \mathrm{F}\)
Electron configuration -2, 7
Period – 3
Group – 17

Question 2.
A, B, C, D are four elements. The electronic configuration is given below and find the answers in the following (Hint. The symbols are not real)
A – 2, 2
B – 2, 8, 5
C – 2, 7
D – 2, 8, 2
a) Find the elements belongs to same period?
b) Find the elements belongs to same group.
c) ‘C’ belongs to which period and group?
Answer:
a) B, D, and A, C because the number of shells are same.
b) A, D because the number of electrons in the outermost shell is same.
c) ‘C’ belongs to second period and 17th group

Question 3.
Table given below lists the contributions and names of scientists who made earlier attempts in the classification of elements. Make them in the correct order.

Answer:

Question 4.
An incomplete form of the periodic table is given below.
write answers in the question connecting the position of elements in it.

1. Which element has the largest atomic size in group I?
2. Write the transition elements?
3. Which element has the lowest ionization energy in the 2nd period?
4. Which element belongs to Noble gas elements?
5. Compare L, M which element has the lowest electronegativity?
6. Write the element belongs to Halogen family?
Answer:
1. D
2. F, G, H
3. C
4. N
5. L
6. M

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Kerala State Syllabus 8th Standard Hindi Solutions Unit 2 Chapter 3 मेरे बच्चे को सिखाएँ (पत्र)

मेरे बच्चे को सिखाएँ पाठ्यपुस्तक के प्रश्न और उत्तर

Mere Bache Ko Sikhaye Notes 8th Kerala Syllabus प्रश्ना 1.
“मेहनत से कमाया एक पैसा भी, हराम में मिली नोटों की गड्डी से कहीं अधिक मूल्यवान होता है।” अपना दृष्टिकोण प्रकट करें।

उत्तर:
यह कथन बिलकुल ठीक है। हराम की चीजें हमारे हक का नहीं है। मेहनत से कमाया पैसा ही मूल्यवान है। मानव को ईमानदारी के साथ जीना है। मेहनत ईमानदारी में चार चाँद लगाता है।

Kerala Syllabus 8th Standard Hindi Notes प्रश्ना 2.
‘बदमाशों को आसानी से काबू में किया जा सकता है। ऐसा क्यों कहा होगा?

उत्तर:
बदमाशों के अंदर भी कुछ सच्चाई होती है। उपदेश और सत्संग के द्वारा उन सच्चाइयों को बाहर ला सकते हैं। इसलिए ऐसा कहा गया है।

Hindi State Syllabus 8th Standard प्रश्ना 3.
‘नकल करके पास होने से फेल होना बेहतर है’ इस प्रस्ताव से क्या आप सहमत है? क्यों?

उत्तर:
मैं इससे शतप्रतिशत सहमत हूँ। नकल से मिली जीत में ज्ञान की गहराई नहीं होती। यह तत्काल लाभ दे सकता है। लेकिन भविष्य में इससे कोई मुनाफ़ा नहीं होता। इसलिए फेल से सीख लेना ही बेहतर है।

8th Standard Hindi Guide Kerala Syllabus प्रश्ना 4.
‘भीड़ से अलग होकर अपना रास्ता बनाना’ का मतलब क्या है?

उत्तर:
भीड़ एक ही मानसिकता के आधार पर चलती है। भीड़ की मानसिकता से अलग होकर सोचने से ही नई दृष्टि और नए विचार मिलते हैं। इस नए दृष्टिकोण से ही सामाजिक प्रगति संभव होती है। संसार के सभी महत् व्यक्ति इस प्रकार सोचनेवाले थे। इसलिए उन्हें संसार में बदलाव ला सका।

मेरे बच्चे को सिखाएँ Textbook Activities

8th Standard Hindi Notes State Syllabus प्रश्ना 1.
लघु-लेख लिखें।
‘सफल जीवन’ विषय पर लघु-लेख लिखें।

उत्तर:
सफल जीवन
जीवन को सफल बनाने के लिए मनुष्य को आत्मविश्वास, दृढ़संकल्प, अदम्य उत्साह और लगन चाहिए। केवल पढ़ने से ही नहीं, अच्छे चरित्र के निर्माण में भी मानव को ध्यान देना चाहिए। उसे परिश्रमी होना चाहिए। उसे यह समझना चाहिए कि नुशासन जीवन को सफल और उज्ज्वल बनाने के लिए आवश्यक है। व्यक्ति को सादा जीवन और उच्च विचार का आदर्श ग्रहण करना चाहिए। उसे बुरी आदतों और बुरे सहवास से बचकर रहना भी होगा। अपने पाठों को लगन से पढ़ना, बड़ों के सदुपदेशों का पालन करना, बड़ों से आदर और छोटों से प्यार करना आदि की आवश्यकता है। उसे पथभ्रष्ट करनेवाली बातों से बचकर रहना भी चाहिए। जो व्यक्ति इस प्रकार का जीवन बिताएगा, वह अपने जीवन में सफल बनेगा।

मेरे बच्चे को सिखाएँ मेरी रचना में

उचित चौकार में ✓ लगाएं।


विषय का विश्लेषण किया है।

प्रस्तुतीकरण में क्रमबद्धता है।

उचित भाषा का प्रयोग किया है।

अपना दृष्टिकोण प्रस्तुत किया है।

उचित शीर्षक दिया है।

मेरे बच्चे को सिखाएँ Summary in Malayalam and Translation

मेरे बच्चे को सिखाएँ शब्दार्थ Word meanings

Students can Download Maths Chapter 12 Proportion Questions and Answers, Summary, Notes Pdf, Activity in Malayalam Medium, Kerala Syllabus 9th Standard Maths Solutions helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Maths Solutions Chapter 12 Proportion in Malayalam Medium

Proportion Questions and Answers in Malayalam

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पिता का प्रायश्चित पाठ्यपुस्तक के प्रश्न और उत्तर

Pitha Ka Prayaschit Questions And Answers Kerala Syllabus 8th प्रश्ना 1.
वह झूठ बोला, “कार तैयार नहीं थी, इसलिए देर हो गई।” इस तरह झूठ बोलना क्या सही है? क्यों?

उत्तर:
झूठ बोलना कभी भी सही नहीं है। क्योंकि यह एक बुरी आदत है। झूठ बोलने से तत्काल फ़ायदा हो सकता है। लेकिन इससे भविष्य में नुकसान ही होगा।

Pitha Ka Prayaschit Notes Kerala Syllabus 8th प्रश्ना 2.
“घर तक की अठारह मील की दूरी पैदल चलकर ही तय करूँगा।” मनीलाल गाँधी के इस निर्णय से आप सहमत हैं? क्यों?

उत्तर:
मनीलाल गाँधी का यह निर्णय बिलकुल सही है। क्योंकि बेटे की गलती का कारण वे अपने को मानते हैं। इसके द्वारा उन्होंने अपने बेटे को अपनी गलती पर सोचविचार करने मौका दिया।

पिता का प्रायश्चित Textbook Activities

Pitha Ka Prayaschit In Malayalam Kerala Syllabus 8th प्रश्ना 1.
सही मिलान करें।


उत्तर:
वर्ष — बरस
सुदूर — दूरदराज
प्रदेश — इलाका
अवसर — मौका
प्रतीक्षा — इंतज़ार
ढूँढ़ — तलाश

Prayashchit Hindi Lesson Question Answer Kerala Syllabus 8th प्रश्ना 2.
अर्थभेद समझें।

डरबन से 18 मील दूर एक आश्रम में रहता है।

डरबन से 18 मील दूर एक आश्रम में रहता था।

मैं और मेरी दो बहिनें हमेशा शहर जाने की इंतज़ार में रहते हैं।

मैं और मेरी दो बहिनें हमेशा शहर जाने की इंतज़ार में रहते थे।

वहाँ दूर तक गन्ने के खेत हैं।

वहाँ दूर तक गन्ने के खेत थे।

Prayaschit Questions And Answers Kerala Syllabus 8th प्रश्ना 3.
पत्र लिखें।

संस्मरण कैसा लगा? पुत्र की गलती पर पिता ने अपने आप को सज़ा दी। इसी दर्द के एहसास से अरुण गाँधी ने यह निर्णय लिया- मैं कभी झूठ नहीं बोलूँगा। अपना दर्द वह दोस्त से बाँटे बिना नहीं रह सका। उसने मित्र को पत्र लिखा। वह पत्र कल्पना करके लिखें।

उत्तर:

डरबन
20 अगस्त 1950

प्रिय मित्र,
नमस्कार।
तुम कैसे हो? सोचता हूँ कुशल से हो। हम यहाँ डरबन में खुशी से जी रहे हैं। अपने जीवन के एक विशिष्ट बात बताने के लिए मैं यह चिट्ठी लिख रहा हूँ। कल पिताजी को मेरी गलती पर प्रायश्चित करना पड़ा। हुआ यह कि पिताजी को शहर में कल एक मीटिंग थी। उन्हें मैंने कार से शहर छोड़ा। शाम पाँच बजे उन्हें लेने जाना था। लेकिन बेन जॉन का सिनेमा देखकर मैं समय भूल गया। देरी के कारण पूछने पर झूठ बोला कि कार ठीक करके गैरेज से नहीं मिला। लेकिन पिताजी बात पहले ही समझ गए थे।

पिताजी ने मेरे झूठ को अपनी गलती माना। वे प्रायश्चित करते हुए घर तक का रास्ता पैदल चले। यह देखकर मुझे बहुत दुख हुआ। मैं यह निश्चय किया हूँ कि आइंदा झूठ नहीं बोलूंगा। अगर पिताजी मुझे कोई सज़ा दी होती तो मैं ऐसा कोई निर्णय नहीं लेता। मैं यह घटना कभी नहीं भूलूँगा। उसकी याद ज़िंदगी में मुझे सही रास्ते पर ज़रूर ले जाएगी।

अपना दोस्त
अरुण गाँधी।

सेवामें

अरविंद
वर्धा आश्रम
पोरबंदर
गुजरात
भारत

पत्र लिखते समय ध्यान दें…
स्थान और तारीख है।
उचित संबोधन है।
विषय का सही संप्रेषण है।
स्वनिर्देश है।
पता है।

पिता का प्रायश्चित मेरी रचना में

उचित चौकोर में ✓ लगाएँ।


स्थान और तारीख हैं।

उचित संबोधन है।

विषय का सही संप्रेषण है।

स्वनिर्देश है।

पता है।

पिता का प्रायश्चित Summary in Malayalam and Translation

पिता का प्रायश्चित शब्दार्थ Word meanings

You can Download Chemical Bonding Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 9th Standard Chemistry Solutions Part 1 Chapter 2 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 9th Standard Chemistry Solutions Chapter 2 Chemical Bonding

Chemical Bonding Textual Questions and Answers

Kerala Syllabus 9th Standard Chemistry Notes Chapter 2 Question 1.
What peculiarity do you see in the electronic configuration of noble elements except Helium? Except Helium all other elements have 8 electrons in the outermost shell, hence shall be considered to be chemically stable.

The arrangement of eight electrons in the outermost shell of atom is called octet electron configuration. In Helium atom there is only one shell. The maximum number of electrons in the first shell is 2. Hence two-electron pattern system of Helium also stable.

Kerala Syllabus 9th Standard Chemistry Chapter 2 Question 2.
The electronic configuration of some elements are given below.

Is the number of electrons in the outermost shell of these elements the same as that of the elements in Table (2.1).
Answer:
No

(i) You are familiar with the compounds of these elements. Write the names of some compounds?
Answer:
Magnesium chloride, Sodium oxide, Sodium chloride.

(ii) How are atoms in these compounds held together?
Answer:
Strong attractive force

(iii) What is meant by Chemical Bonding?
Answer:
The attractive force that holds the atoms together in the formation of a molecule is called chemical bonding.

Ionic Bonding

Class 9 Chemistry Chapter 2 Notes Kerala Syllabus Question 3.
In the formation of sodium chloride which atoms are combing.
Answer:
Sodium, chlorine

Chemical Bonding Notes Class 9 Kerala Syllabus Question 4.
How many electrons are there in the outermost shell of sodium atom?
Answer:
1

Chemical Bonding Questions And Answers Class 9 Kerala Syllabus Question 5.
How many electrons are there in outermost shell of chlorine?
Answer:
7

Chemical Bonding Questions And Answers Pdf Class 9 Kerala Syllabus Question 6.
How do chlorine and sodium attain stability?
Answer:
Sodium donates one electron to chlorine to become sodium ion [Na+] and chlorine become chloride ion [Cl]

Chemical Bonding Class 9 Notes Pdf Kerala Syllabus Question 7.
Analyze the electron transfer in each atom during the formation of sodium chloride.
Answer:

Chemical Bonding Class 9 Pdf Kerala Syllabus Question 8.
Draw the electron dot diagram of the transference of electron of sodium atom and chlorine atom. The diagram represents only electrons in the outermost shell because they are the only electrons participating- in chemical bonding.
Answer:

Questions On Chemical Bonding Class 9 Kerala Syllabus Question 9.
Complete Table 2.3 by examining the arrangement of electrons before and after the chemical reaction during the formation of sodium chloride.

a) Which atom donates electron? How many electrons?
b) Which atom accepts electron? How many electrons?
Answer:
a) Sodium, one electron
b) Chlorine, one electron

Kerala Syllabus 9th Standard Chemistry Notes English Medium Question 10.
Electron transfer during the formation of sodium chloride can be written in the form of an equation
Na → Na⁺+1e^–
Cl + 1e^– → Cl^–
Answer:
During the formation of sodium chloride sodium atom donates electron and gets converted to sodium ion (Na⁺) chlorine accepts an electron to form chloride ion (Cl^– ). Through this sodium and chlorine atoms complete an octet in their outermost shell to attain stability.

The oppositely charged ions thus formed are held together by electrostatic force of attraction. This attractive force is called Ionic Bond. Sodium chloride contains ionic bond.

Kerala Syllabus 9th Standard Chemistry Chapter 1 Question 11.
Define Ionic Bond?
Answer:
Ionic bond is a chemical bond formed by electron transfer in an ionic bond, the ions are held together by the electrostatic force of attraction between the oppositely charged ions.

Kerala Syllabus 9th Standard Chemistry Solutions Question 12.
Explain the formation of magnesium oxide from magnesium and oxygen?
Analyze the electron dot diagram and complete the table.
Answer:

To attain stability magnesium donates 2 electrons to become magnesium ion (Mg₂⁺) and – oxygen become [O₂^– ] ion. This type of bonding is ionic bonding.

Chemical Bonding Notes Class 9 Pdf Kerala Syllabus Question 13.
How the ionic bond formation of sodium oxide is represented?
[Hint: Atomic No. of sodium 11, oxygen 8]
Answer:

Question 14.
Draw the electron dot diagram of following compounds. [Hint: Atomic No. Na=11, F=9, Mg=12]
Answer:
1. Sodium Flouride [NaF]

Question 15.
Define ionic compounds?
Answer:
Compounds formed by ionic bonding are called ionic compound.

Covalent Bonding

Fluorine [F₂], Chlorine [Cl₂] oxygen [O₂] Nitrogen [N₂] etc. are diatomic molecules. Let us examine the formation of these molecules.
The Bohr atom model of fluorine is given in figure.

Question 16.
Write the atomic number of fluorine?
Answer:
9

Question 17.
The electronic configuration of Fluorine
Answer:
2, -7 ‘

Question 18.
How many electrons are required for one fluorine atom to attain the octet?
Answer:
1

Question 19.
Is there a possibility of transferring electrons from one fluorine atom to another fluorine atom?
Answer:
No.

Question 20.
How can the two fluorine atoms attain an octet arrangement?
Answer:
By sharing of electrons

Question 21.
The manner in which the two fluorine atoms in a fluorine molecule undergo chemical bonding is illustrated in fig. 2.6.
Answer:

Question 22.
What happens during the formation of fluorine molecule electron transfer or electron sharing?
Answer:
Electron sharing

Question 23.
How many pairs of electrons are shared?
Answer:
One pair

Question 24.
How covalent bonds are formed?
Answer:
The chemical bond formed as a result of the sharing of electrons between the combining atoms is called a covalent bond.

Question 25.
How single bonds are formed?
Answer:
Single bonds are formed by sharing one pair of electrons. It is represented by a small line between the symbols of the combining element, eg. Fluorine molecules can be represented as F – F. The atomic number of chlorine is 17.

Question 26.
Write down the electronic configuration?
Answer:
2, 8, 7

Question 27.
Draw the electron dot diagram of the formation of chlorine molecule by combining two chlorine atoms?
Answer:

Here one pair of electrons – sharing hence single bond is formed.

Question 28.
Examine the diagram illustrating the chemical bonding in the molecule of oxygen and nitrogen.
Answer:

In oxygen molecules, two pairs of electrons are shared hence this type of covalent bond is double bond.
In nitrogen molecule, three pairs of electrons are shared hence this type of covalent bond is triple bond.

Question 29.
Complete table 2.5 given below related to covalent bonding.

Answer:

Question 30.
Draw the chemical bond formation of hydrogen chloride [HCI]

a) How many electron pairs are shared?
b) Represent chemical bond by using symbols?
Answer:
a) One pair of electrons
b) H – Cl

Question 31.
Examples of some covalent compounds are given draw the chemical bonds of the compound by using electron dot diagram.
a)CH₄
b) HF
c)H₂O
Answer:
a)

Electronegativity

Question 32.
Define electronegativity?
Answer:
In a covalent bond the relative ability of each atom to attract the bonded pair of electrons towards itself is called electronegativity.

Question 33.
Who proposed the electronegativity scale?
Answer:
Linus Pauling

Question 34.
Some compounds and their nature are shown in table (2.6) complete the table by finding out the electron negativity difference between the constituent elements.

Answer:

Generally, the electronegativity difference of the component elements in a compound is 1.7 or more it shows ionic character. If it is less than 1.7 it shows covalent character.

Polar Nature

Question 35.
Consider the case of hydrogen molecule [HCl]
a) What is the electronegativity of hydrogen?
b) What is the electronegativity of chlorine?
c) The atomic nucleus of which of these elements has a greater tendency to attract the shared pair of electrons?
d) The chlorine atom with a higher electronegativity attracts the shared pair of electrons towards its nucleus. As a result, the chlorine atom in hydrogen chloride develops a partial negative charge g: (delta negative) and hydrogen atom develops a partial positive charge δ+ (delta positive) it can be represented below
Answer:
a) 2.2
b) 3.16
c) Chlorine
d) \(\begin{array}{l}{\delta^{+} \quad \quad \delta^{-}} \\ {H-C^{\prime}}\end{array}\) Compounds having partial electron charge separation with the molecule are called polar compound. HF, HBr, H20 are example of polar compounds.

Question 36.
Explain the properties of Ionic compounds and covalent compounds.
Answer:

Valency:

Question 37.
What is meant by valency?
Answer:
Valency is the combining capacity of the atoms of an element. It can be treated as the number of electrons lost gained or shared by an atom during chemical combination.

Question 38.
In the formation of sodium chloride- sodium donates one electron, chlorine accepts one electron write the valencies of each element?
Answer:
1

Question 39.
In the formation of magnesium oxide- How many electrons are donated by magnesium?
Answer:
2

Question 40.
How many electrons are accepted by oxygen?
Answer:
2

Question 41.
How is valency and electron transfer related in this case?
Answer:
Same

Question 42.
In the formation of hydrogen chloride, how many electron pairs are shared?
Answer:
One pair

Question 43.
What will be the valency of each atom?
Answer:
1

Question 44.
Complete the table given below analyze the change in the electronic arrangement of elements during the formation of each compound. Find how they are related to valency.

Answer:

From Valency to Chemical Formula

The chemical formula of some compounds are given
Sodium chloride – NaCl
Magnesium chloride – MgCl₂
Aluminium chloride – AICl₃
Carbon tetrachloride – CCl₄

Question 45.
The symbol of some elements and there valencies are given. Write the chemical formula of the compounds formed by them.

Answer:

Question 46.
Why does the number of chlorine atoms differ in these compounds? Try to find out by analyzing the valency of the elements Na, Mg, Al, Cl and C. Analyse Table 2.9
Answer:

Examine the above table and identify how to write the chemical formula from valency. Compare your findings with the following.

• First write the element with lower electronegativity.
• Exchange the valency of each element and write as suffix.
• Divide the suffix with the common factor.
• If the suffix is 1, it need not be written.

Let Us Assess

Question 1.
Complete the table given below and answer the following questions (symbols used are not true)

a) Which element in the table is the most stable one? Justify your answer.
b) Which element donates electrons in chemical reaction?
c) Write the chemical formula of the compound formed by combining element S with P.
Answer:

a) R – it contains an octet configuration in the outermost shell.
b) S
c) The valency of S = 2 and P is 1, hence the chemical formula

[The element in which the electron lose can be written first]

Question 2.
Electronegativity values of some elements are given. Using these values, find whether the following compounds are ionic or covalent.
(Electronegativity of Ca = 1, O = 3.5, C = 2.5, S = 2.58, H = 2.2, F = 3.98)
i) Sulphur dioxide (S02)
ii) Water (H₂O)
iii) Calcium fluoride (CaF₂)
iv) Carbon dioxide (CO₂)
Answer:
i) SO₂
Electronegativity difference = 3.5 – 2.58 = 0.92
If the electronegativity difference is less than 1.7, it shows covalent character.
ii) Water (H₂O)
Electronegativity difference = 3.5 – 2.2 = 1.3
If the electronegativity difference is less than 1.7 it forms covalent compounds.
iii) CaF₂
Electronegativity difference = 3.98 -1.0 = 2.98
If the electronegativity difference is greater than 1.7 if forms ionic compounds.
iv) CO₂
Electronegativity difference = 3.5 – 2. 5 = 1.0
If the electronegativity difference is less than 1.7 it shows covalent compounds.

Question 3.
Some elements and their valencies are given

a) Write the chemical formula of barium chloride
b) Write the chemical formula of zinc oxide
c) The chemical formula of calcium oxide is CaO. What is the valency of calcium?
Answer:

c) The valency of calcium is 2.

Question 4.
Examine the following chemical equations and answer the questions.
(Hint: Atomic Number Mg = 12 Cl = 17)
Mg + Cl₂ → MgCl₂
Mg → Mg²⁺ + ……..
Cl + 1e^– → ………..
a) Complete the chemical equations.
b) Which is the cation? Which is the anion?
c) Which type of chemical bond is present in MgCl₂?
Answer:
a) Mg → Mg^2- + 2e
Cl + 1e^– → Cl^–
b) The cation or positively charged ion is Mg²⁺ and the anion or negatively charged ion is Cl^–
c) Ionic Bonding

Extended Activities

Question 1.
Draw the electron dot diagram of chemical bonds in methane (CH₄) and ethane (C₂H₆).
Answer:

Question 2.
P, Q, R, S are four elements. Their atomic numbers are 8, 17, 12 and 16 respectively. Find the type of chemical bond in these compounds formed by combining the following pairs of elements. Construct and exhibit the type of bonds using different. substances (eg. pearls) (Electronegativity values:
P = 3.44, Q = 3.16, R = 1.31, S = 2.5)
1) P, R
2) P, S
3) Q, R
Answer:
1. PR
Electronegativity difference = 3.44 – 1.31 = 2.13
The electronegativity difference is greater 1.7 it shows ionic compound.
2. PS
Electronegativity difference = 3.44 – 2.58 = 0.86
The electronegativity difference is less than 1.7 it shows covalent compound.
3. QR
The electronegativity difference = 3.16 – 1.31 = 1.85
The electronegativity difference is greater than 1.7 it shows ionic compound.

Question 3.
Perform the experiments arranging the apparatus as shown in figure.

Record your observations and identify what type of compounds sodium chloride and sugar are
Answer:
When electricity is passed through sodium chloride solution in which carbon rod is immersed hydrogen and chlorine gas are produced. It is an ionic compound. In the second when electricity is passed through sugar solution there is no charge. Hence it belongs to covalent compound.

You can Download Construction of Quadrilaterals Questions and Answers, Activity, Notes, Kerala Syllabus 8th Standard Maths Solutions Chapter 6 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 8th Standard Maths Solutions Chapter 6 Construction of Quadrilaterals

Construction of Quadrilaterals Text Book Questions and Answers

Textbook Page No. 108

Construction Of Quadrilaterals Class 8 State Syllabus Question 1.
Can you draw these patterns of squares in your notebook?


Solution:
1. Draw a square of side 6 cm. Draw lines horizontally and vertically 2cm apart. Rub off unwanted parts. We get the required pattern.

2. Draw a square of side 7 cm. In it draw horizontal and vertical lines at intervals of 4 cm, 2 cm and 1 cm. Erase the unwanted part. We get the required pattern.

3. Draw a square of diameter 6 cm. (Draw a circle of diameter 6 cm and draw two perpendicular diameters. Join their ends.) Mark the points on diagonal 2 cm a part. Join the points as in the following figure. Rub off the unwanted part. We get the required pattern.

Text Book Page No. 111

Class 8 Mathematics Construction Of Quadrilaterals Kerala Scert Solutions Question 2.
Draw the figures below in your notebook.


Solution:
1. Draw a rectangle of diagonal 9 cm and angle between the diagonal and one side is 30°. Mark a point on the diagonal at a distance 6 cm from one end of the diagonal. Draw lines perpendicular to the sides of the rectangle through this point. Erase unwanted parts, we get the required pattern.

2. Construct an equilateral triangle with side 3 cm.

The other two sides of a triangle are made by equal diagonals of the rectangle. Then the diagonal of the rectangle is 6 cm. Draw a rectangle in a horizontal position with diagonals 6 cm and the angle between the diagonals 60°. Draw another rectangle of the same measure in the vertical position at the middle of the first rectangle. Draw the wanted part in bold lines. Erase unwanted part.

Construction Of Quadrilaterals Class 8 Kerala Syllabus Question 3.
Draw a rectangle CBD, which di agonal (AB) is 6 cm and AC making an angle 30° with AB. The arc with centre at B and BC as radius and the arc with centre at A and AC as radi us meet at E. Complete ∆ AEB. Draw an arc with centre A and EB as radi us. Also draw arc with B as centre and AE as radius meet at F. Complete the rectangle AEBF.

Text Book Page No. 114

8th Class Maths Construction Of Quadrilaterals Kerala Syllabus Question 3.
Draw a rhombus of diagonals 5.5 cm and 3 cm in your notebook.
Solution:
Draw a line of length 5.5 cm, and find its midpoint by drawing the perpendicular bisector. Mark the points on the upper and lower part of the bisector.
Mark the points on the upper and lower part of the bisector line at a distance 1.5 cm from the intersecting point of the first line and perpendicular bisector. Join these points to the end of the first line.

Construction Of Quadrilaterals 8th Class Kerala Syllabus Question 4.
Draw also a rhombus of diagonals 5.5 cm and 3.5 cm.
Solution.
It is difficult to measure 1.75 cm (half of 3.5 cm) using scale, so draw a rectangle of 5.5 cm and breadth of 3.5 cm. By drawing the perpendicular bisectors find the midpoints of the sides. By joining the midpoints of the sides, we get a rhombus.

Textbook Page No. 117

Class 8 Construction Of Quadrilaterals Kerala Syllabus Question 5.
Draw these figures
Solution:
1. Two equal rhombuses :


Solution:
1. From the figure two sides of A BCD are equal, angles opposite these sides are also equal. We can calculate them as 50° each. In the same way find other angles in the figure.

Draw a line BD vertically, 3 cm long. At D draw angles of 50° on both sides. At B also draw angles of 50° on both sides. Then we get a rhombus ABCD. Extend BC to G such that BC = CG and extend DC to E such that DC = CE. Draw GE. Draw angle of 50° at G and E to find F.

2. Draw a circle of radius 2 cm. Divide the centre of the circle into angles of 60° each. These lines meet the circle at the points A, B, C, D, E and F.

Draw arcs of 2 cm from A and B to get G. Similarly find H and I. Draw the required parts and rub off unwanted parts.

Construction of Quadrilaterals Class 8 Question 3. Draw a circle of radius 2 cm. Mark the points A, B, C, D, E, F, G, and H on the circle by making 45° angles at the centre. Draw arc of 2 cm A and B to get I. Similarly find J, K and L. We get the required figure.

4. Draw AC, 4 cm long and mark its midpoint B. Since all are rhombuses, ABI is a equilateral triangle. Its angle are 60° each.

In the rhombus BCDJ, ∠ JBC = ∠JDC = 60°, ∠BCD = ∠BJD = 120°
In the rhombus BJFI, ∠IBJ =∠IFJ = 60°, ∠BJF = ∠FIB = 120°. Draw each rhombus and complete the pattern.

5. Draw a line AB, 4 cm long and mark its midpoint C. CJFI is a square, all its angle are 90° each. Also calculate ∠ICA = 45° and ∠CAH = 135°. Taking measures of the sides and angles draw each rhombus.

6. Draw a square of side 3 cm. And draw two parallelograms with sides 3 cm, 2 cm and angle between them 45°, on the sides of the square.

Text Book Page No. 124

Construction Of Quadrilaterals Class 8 Solutions Kerala Syllabus  Question 6.
Draw the figures below :
1. Three equal isosceles trapeziums:



Solution:
1. Draw DE, 5 cm long and mark G on DE such that DG = 2 cm (length of AB) ∆ ABC and ∆ DEF are equilateral triangles. Their each angle is 60°. Find B by drawing ∠EGB = ∠BEG = 30°. Draw ∠ADG = 30°and BA = 2 cm to get A. Now we got one trapezium. Draw the other two trapezium in the same way.

2. Draw two circle of radius 1 cm and 3 cm with the same centre. Divide the circumferance of the both circle into 6 equal parts. And join them to obtain six equal isosceles trapeziums.

3. Draw two parallel sides AB = 8 cm, CD = 4 cm. AE= FB = 2 cm, EF = 4 cm. Also GD = HC = 2 cm. ∠B + ∠B CD = 180°. The angles at C are equal. They are equal to B. So ∠B = \(\frac{180}{3}\) = 60°. ∠A = 60°. Now draw the pattern.

4. Draw a rectangle with length 8 cm and breadth 4 cm. Divide this rectangle into two squares with side 4 cm. Consider one square and half of second. Mark the midpoint of the sides. Join as in the figure.

5. Draw a square of side 8 cm. And draw lines horizontally and vertically 2cm apart. Complete the figure.

Text Book Page No. 128

8th Class Maths Notes Kerala Syllabus Question 7.
Draw the quadrilaterals shown below.

Solution:
1.Draw AB = 5 cm. Draw AD such that ∠A = 80° and AD =3 cm. Mark C such that ∠D = 120° and DC = 4 cm. Join BC.

2. Draw AB = 5 cm. Draw AD such that ∠A = 60° and AD = 3 cm. Mark point C such that ∠B = 80° and ∠D = 100°. Join DC and BC and complete the quadrilateral ABCD.

3. Draw a ABD with AB = 7 cm, BD = 8 cm and AD = 4 cm. Mark the point C at a distance 6 cm from A and 5 cm from D. Join BC and CD.

Construction of Quadrilaterals Additional Questions and Answers

Class 8 Maths Construction Of Quadrilaterals Kerala Syllabus Question 1.
In the figure, ABCD is a square whose diagonals intersect at O. If AD = 10 cm, find the length of BD and CD ?

Solution:
Tn a square diagonal are equal and perpendicular bisectors of each other.
OD = 5 cm and OC = 5 cm.
CD² = OD² + OC² = 5² +5² = 50 cm
CD = \(\sqrt{50}\) = BD = \(5\sqrt{2}\) cm.

Kerala Syllabus 8th Standard Maths Notes Question 2.
Draw quadrilateral PQRS, PQ = 7 cm, QR = 5 cm, RS= 4cm, ∠Q = 60° and ∠R = 140°.
Solution:
Draw PQ = 7 cm and draw QR of length 5 cm which makes an angle 60° with PQ. Draw RS such that RS = 4 cm and ∠R = 140°.

8th Standard Maths Notes State Syllabus Question 3.
(a) Write any two peculiarities of the diagonals of a square.
(b) The length of a diagonal of a square is 7 cm. Draw the square.
Solution:
(a) The diagonals of a square are equal.
The diagonals bisect each other perpendicularly.
(b)

Question 4.
In rhombus PQRS , PR = 7 cm and Question = 5 cm. Construct rhombus PQRS.
Solution:

Question 5.
In the figure, ABCD is a parallelogram. ∠D = 80°. Find all other angles?

Solution:
ABCD is a parallelogram
Opposite angles are equal ∠B = 80°.
Sum of the angles on the same side is 180°.
∠A + ∠B = 180°.
∠A = 180° – 80° = 100°
And ∠C = 100° (opposite angles are equal).

Question 6.
In the figure, ABCD is a parallelogram. Find x, y, z.

Solution:
∠Y = 112° (opposite angles are equal)
In ADC, ∠x + ∠y + 40 = 180° (sum of angles in a triangle)
∠x + 112° + 40° = 180°
∠x = 180° – 152° = 28°
∠z = 28°(transversal alternate interior angles are equal).

Question 7.
Construct a quadrilateral ABCD, AB = 6 cm, BC = 3 cm, CD = 2 cm, AD = 4 cm and AC = 5 cm.
Solution:
Draw AB = 6 cm. Then find C by drawing arcs of radius 5 cm and 3 cm from A and B. Find D by drawing arcs of radius 4 cm and 2 cm from A and C. Join BC, CD and AD to get quadrilateral ABCD.

Question 8.
Construct a quadrilateral ABCD, AB = 8 cm, BC = 6 cm, CD = 5.5 cm, DA = 3 cm and ∠B = 50°.
Solution:
Draw AB = 6 cm. Draw BC such that BC = 6 cm and ∠B = 50°. Draw an arc of radius 5.5 cm with C as centre and another arc of radius 3 cm with A as centre. Mark the point of intersection as D. Join CD and AD.

Question 9.
In parallelogram ABCD, the diagonals AC and BD intersect at O. AC = 6.5 cm, BD = 7 cm and ∠AOB = 100°. Construct the parallelogram.
Solution:

Question 10.
The diagonals of a rhombus are of lengths 16 cm and 12 cm. What is its perimeter?
Solution:

In right angled AOB,
AO = 8 cm, BO = 6 cm, ∠AOB = 90°
AB² = AO² + BO² = 8² + 6²
= 64 + 36 = 100
Side, AB = \(\sqrt{100}\) = 10 cm
Perimeter = 4 × 10 = 40 cm.

Question 11.
Draw the following patterns, a. 6 equal rhombuses :
(a) 6 equal rhombuses:

(b) 3 equal rhombuses

Solution:
(a) Draw a circle of radius 2 cm with centre O. Divide the centre of circle into angles of 60° each. These lines meet the circle at the points A, B, C, D, E and F. Draw arc of 2 cm from A and B to get G. In the same way find H, I, J, K, L. Draw needed part.

(b) Draw square of side 4 cm. Draw rhombuses with side 4 cm and an gle 30° on top and bottom side of the square. Complete the figure.

(c) Angles around the point at which three rhombuses joined together is 120° each. Since one angle of the rhombus is 120°, another angle 60°. Draw three rhombuses with side 4 cm and angle 60°. Complete the figure.

(d) Draw a semicircle of radius 2 cm with centre O. Divide the centre of circle into angles of 45° each .These lines meet the circle at the point A, B, C, D and E. Draw arc of 2 cm from A and B to get F. In the same way find G, H and I. Complete the figure.

(e) Draw a rectangle of length 6 cm and breadth 3 cm. Draw two rhombuses on both side of the rectangle which makes angle 45° and 135° with length and breadth respectively.

Question 12.
In a parallelogram ABCD, find x, y, z from the adjoining figure.

Solution:
ABCD is a parallelogram,
∠C = 45° (Opposite angles are equal)
∠C + Z = 180° (linear pair)
Z = 180° – 45° = 135°
45° + Y = 180° (sum of the angles on the same side is 180°)
Y = 180° – 45° = 135°
sinceY = 135°
X = 135°(Opposite angles are equal)

You can Download Chemical Messages for Homeostasis Questions and Answers, Summary, Activity, Notes, Kerala Syllabus 10th Standard Biology Solutions Chapter 3 help you to revise complete Syllabus and score more marks in your examinations.

Kerala State Syllabus 10th Standard Biology Solutions Chapter 3 Chemical Messages for Homeostasis

Chemical Messages for Homeostasis Text Book Questions and Answers

Chemical Messages For Homeostasis Kerala Syllabus 10th Question 1.
Which are the hormones you know? List them?
Answer:

• Insulin
• Thyroxine
• Oestrogen

Hormones:
The endocrine glands play a vital role in coordinating and controlling life activities. Secretions of endocrine glands are called hormones. There secretions are chemical substances that belong to different categories such as proteins, peptides, steroids, fatty acids, etc. Endocrine glands do not have particular ducts carry hormones to various tissues. Hence they are known as ductless glands. Hormones are transported through blood. As these substances regulate cellular activities, they can be called chemical messages to cell.

Chemical Messages for Homeostasis Hormones In Target Cells

The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the combination of each hormone molecule and its receptor. Following this, enzymes are activated within the cell. As a result, certain changes occur in cellular activities.

After Digestion

Pancreas helps in the digestive process. It functions as an endocrine gland too. It secretes two hormones namely insulin and glucagon.
The beta cells in the Islets of Langerhans glucagon.

Action of insulin and glucagon:

Sslc Biology Chapter 3 Questions And Answers Kerala Syllabus Question 2.
Complete the illustration by including the production of hormones that regulate the level of glucose.
Answer:

Sslc Biology Chapter 3 Notes Kerala Syllabus Question 3.
How is the level of glucose in the blood maintained while fasting? Discuss
Answer:
When the level of glucose increases in blood the cells in the Islets of Langerhans produce insulin which converts the excess glucose into glycogen, protection and lipids.

Diabetes Mellitus

Diabetes is clinically referred to as a condition when the level of glucose before breakfast is above 126 mg/100ml of blood. It is caused either by decreased production of insulin or it$ malfunctioning. Symptoms: Increased appetite and thirst, Frequent urination, Traces glucose in urine Diabetes can be controlled through medicine, diet control and insulin injections.

Biology Class 10 Chapter 3 Notes Kerala Syllabus Question 4.
The increase of glucose in blood is said to be diabetes. Shouldn’t one be more energetic if the glucose level in his/her blood rises? What is your opinion? Write them down in your science diary.
Answer:
No. One be more should not energetic if the glucose level in his or her blood. Persons with diabetes experience loss of body weight, weakening of muscles and tiredness.

Regulation Of Metabolism

The anabolic and catabolic processes taking place in the body are metabolism. The thyroid gland is the endocrine gland contrails the metabolic process.

Functions of thyroxine:

10th Class Biology Chapter 3 Kerala Syllabus Question 5.
How would be body activities be affected if sufficient amount of thyroxine is not produced?
Answer:

• Low energy production
• Bloating of body
• Slowing down of heartbeat
• Loss of appetite, lethargy
• Dry skin

Undersecretion of thyroxine – Hypothyroidism:
The deficiency of thyroxine during the fetal stage or infancy leads to mental retardation and stunted growth. This condition is cretinism. Lack of thyroxine in adults leads to myxoedema.

Symptoms of Hypothyroidism:

• Low metabolic rate
• Sluggishness
• Sleeplessness
• Increase in body weight
• Hypertension
• Oedema

Oversecreation of thyroxine – Hyperthyroidism:
The condition in which all life activities controlled by thyroxine are accelerated due to the excessive production of thyroxine is referred to hyperthyroidism.

Symptoms of Hyperthyroidism:

• High metabolic rate
• Rise in body temperature
• Excessive sweating
• Increased heartbeat
• Sleeplessness
• Weight loss
• Emotional imbalance

Goitre:
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine. In an attempt to produce more thyroxine; the thyroid gland enlarges. This condition is called goitre.

Chemical Messages For Homeostasis Notes Pdf Kerala Syllabus Question 6.
What is the importance of thyroxine in controlling life activities?
Answer:
Thyroxine is a hormone that influences metabolism in our body to a great extent.

Biology 3rd Chapter 10th Class Kerala Syllabus Question 7.
What are the problems caused by excessive production of thyroxine?
Answer:

• Energy production increases and body weight decreases
• Increased heartbeat
• Increased appetite
• Shivering of hands and profuse sweating
• Persistent hyperthyroidism may lead to Graves disease, characterized by exophthalmic goiter.

Sslc Biology Chapter 3 Notes Pdf Kerala Syllabus Question 8.
What are the problems due to thyroxine deficiency?
Answer:
The deficiency of thyroxine retards mental and physical growth of children. This condition is called cretinism. In adults the deficiency of thyroxine results in a disease called myxoedema.

Sslc Biology Chapter 3 Solutions Kerala Syllabus Question 9.
How is iodine related to thyroid gland?
Answer:
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine.

Calcitonin:
It helps in maintaining the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood, from the bones.

Parathyroid Gland

The parathyroid gland is situated behind the thyroid gland. This gland secretes a hormone called parathormone. The function of this hormone is to raise the level of calcium in blood

Sslc Biology Chapter Wise Questions And Answers Kerala Syllabus Question 10.
Complete the illustration showing the maintenance of the level of calcium in blood by the action of calcitonin and parathormones
Answer:

The hormone only upto youth:
Thymus gland:
The thymus gland is situated just below the sternum. The major function of thymus gland is to control, the activities and maturation of lymphocytes which help to impart immunity. This gland secretes thymosin, which is active during infancy. Hence it is known the ‘youth hormone’.

During Emergencies

These glands are situated above the kidneys. The outer part of the adrenal gland is known as the cortex and inner part is medulla. The adrenal cortex secretes aldosterone, cortisol and sex hormones. Adrenal medulla secretes epinephrine and norepinephrine.

Class 10 Biology Notes Chapter 3 Kerala Syllabus Question 11.
The structure of the adrenal glands and the hormones produced by them are illustrated below. On the basis of the indicators given, discuss and write down the notes in the science diary.

i) Hormones secreted by the adrenal cortex
ii) The function of cortisol
iii) Maintenance of salt-water balance in the body
iv) The function of epinephrine and norepinephrine during emergencies.
Answer:
(i) Aldosterone and sex hormones are the hormones secreted by the adrenal cortex.
ii) The synthesis of glucose from protein and fat controls inflammation and allergy, slows down the action of defense cells.
iii) Aldosterone is the hormone that helps to maintains salt-water balance in the body by restating the lose of Na⁺ ions and by promoting the elimination of K⁺ ions through sweat, urine, etc.
iv) Epinephrine acts along with the sympathetic nervous system during emergencies. Thus we can resist or withdraw ourselves from such situations. Norepinephrine acts along with epinephrine.

Biological Clock

Pineal gland is seen in centre of the brain. It secretes the hormone, melatonin which helps in maintaining the rhythm of our daily activities. The production of melatonin is high at night and low during the day. When the level of melatonin increases we feel sleepy and when it decreases we wake up. This hormone also controls reproductive activities of organisms.

Behind Growth

Pituitary gland is a bibbed gland situated just below the hypothalamus in the brain. The anterior lobe produces tropic hormones which regulate the functions of other glands. The posterior lobe stores the hormones which are produced in the hypothalamus.

Chemical Messages For Homeostasis Questions And Answers Question 12.
The hormones produced by the anterior lobe is listed in table. Analyse-it and complete the following worksheet in the science diary.


Answer:
A – Stimulates the activity of thyroid giand
B – AdrenoCortico Tropic Hormone(ACTH)
C – Gonado Tropic Hormone(GTH)
D – Stimulates the activity of ovaries
E – Production of milk
F – Growth Hormone (GH) or Somatotropic Hormone (STH)

Hss Live Guru 10th Biology Kerala Syllabus Question 13.
How the variation in the production of somatotropin affects growth.
Answer:
Somatotropin promotes growth of the body during its growth phase. If the production of this hormone increases during the growth phase, it leads to the excessive growth of the body. This condition is gigantism. It causes another stage called dwarfism when its production decreases during the growth phase. Acromegaly is the condition caused by the excessive production of somatotropin after the growth phase. It is characterized by the growth of the bones on face, jaws and fingers.
The Posterior Lobe of pituitary gland – A storage center

The hormones oxytocin and vasopressin, which are secreted from the posterior lobe of the pituitary are actually produced in the neuro-secretory cells of the hypothalamus. The posterior lobe stores these two hormones and Releases them into blood when required.

Hss Live Guru 10 Biology Kerala Syllabus Question 14.
Observe the table and write down your inferences in the science diary.

Answer:
Oxytocin and vasopressin are secreted from the hypothalamus and stored in the posterior lobe of pituitary gland. Through the connecting nerve fibers they are transported to pituitary gland. Oxytocin facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall and facilitates lactation. Vasopressin helps in the reabsorption of water in the kidneys.

Biology Chapter 3 Class 10 Kerala Syllabus Question 15.
Observe illustration given below which shows the action of vasopressin in kidneys. Based on the indicators given discuss and write a note in science diary.

i) The functions of vasopressin in kidneys
ii) The reason for excessive production of urine during the rainy season
iii) The role of vasopressin in preventing loss of water from the body.
iv) Diabetes insipidus
Answer:
i) The hormone vasopressin regulator reabsorption of water and minerals from the glomerular filtrate.. When there is a reduction in the amount of water in blood, the production of vasopression increased. It accelerates the rate of reabsorption of water. When the quantity of water in blood increases the production of vasopressin decreases. As a result, the rate of reabsorption is also reduced.

ii) During rainy season, sweat production reduces. So the water loss through sweat is decreased. It wingcase the quantity of water in our body Comparatively high. Such situations demand elimination of excess water through urine.

iii) The production of vasopressin increases when there is a need to reduce loss of water through urine. As a result of this, more water is reabsorbed to the blood from kidneys, Thereby the loss of water through urine is reduced and regulate water loss in our body.

iv) The rate of resorption of water in the kidney is decreased when there is no sufficient amount of vasopressin. Hence excess amount of urine is excreted. This condition is called diabetes insipidus Symptoms include frequent urination.

Behind Sexual Characteristics

Testes and ovary, the male and female sex organs respectively, secrete different types of hormones.

Prepare a table by including hormone, centre of production and function:

Prime Controller

Oxytocin and vasopressin are secreted by the hypothalamus. In addition to this hypothalamus controls the pituitary gland by secreting a variety of releasing hormone are inhibitory hormones.

Biology Chapter 3 Class 10 Notes Kerala Syllabus  Question 16.
Observe the illustration given below on the functions of releasing hormones and inhibitory hormones. On the basis of indicatiors discuss and writes it down in the science diary.

i) Action of releasing hormone
ii) Influence of tropic hormones in different glands.
iii) Action of inhibitory hormones
Answer:
i) Stimulates the anterior lobe of the pituitary and secretes tropic hormones.
ii) Tropic hormones stimulate the production of hormones of certain other important glands.
iii) Inhibits the production of tropic hormones in the anterior lobe of the pituitary gland.

Chemical Messages For Communication

Pheromones: Pheromones are chemical substances that are secreted in trace amounts to the surrounding in order to facilitate communication among organisms. Pheromones help in attracting mates, to inform the availability of food, to determine the path of travel and to inform about dangers.
Eg:- Musk in the nusk deer, civet on in civet cat, Bombycol in female silkworm.

Plant Hormones

There are certain chemical substances in plant cells to control and co-ordinate life activities. These are also called plant growth regulators.

Question 17.
Observe the illustration, which show plant hormones and their functions and complete the following table suitably.


Answer:
a) Cell growth, cell elongation, fruit formation
b) Controls the dormancy of embryo in the seeds, dropping to leaves and fruits wilting of leaves, flowering, etc.
c) Gibberellins
d) Promotes cell division cell growth
e) Ethylene.

Artifical Plant Hormones

Auxins: NaphtheleneAceticAcid (NAA), Indol Butyric Acid (IBA), etc., are used for sprouting and the prevention of dropping of premature fruits. 2.4-D (2, 4-Dichloro phenoxy acetic acid) is used as a weedicide.

Gibberellins: It is used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist in marketing.

Abscisic acid: As it accelerates the dropping of fruit, it is used for harvesting fruits at the same time.

Ethylene: Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc. Ethyphon, a chemical which is available in liquid form gets transformed into ethylene when used in rubber trees, and it increases the production of latex.

Chemical Messages for Homeostasis Let Us Assess

Question 1.
Identifying the word-pair relationship and fill in the blank.
Thyroxine: Thyroid gland
Epinephrine:…………..
Answer:
Adrenal gland

Question 2.
Analyze the information given in the box and answer the questions.
X- The production of this hormone is more in night and less in day time.
Y – Hormones from the adrenal gland work along with the sympathetic system.
(a) Identify and name the hormone ‘X’ and its gland.
(b) Identify the hormones indicated as ‘Y’.
Answer:
a) Melatonin pineal gland
b) Epinephrine (Adrenaline)
c) Norepinephrine (Noradrenline)

Question 3.
Analyse the illustration and complete the table appropriately.


Answer:

Question 4.
The hormone that helps in the reabsorption of water in the kidneys.
a) TSH
b) ACTH
c) ADH
d) GTH
Answer:
ADH

Chemical Messages for Homeostasis Extended Activities

1. Conduct a seminar on the topic – The role of the Endocrine system in maintaining homeostasis’.
Main points:-

• Situations which lead to change in homeostasis
• How is homeostasis reinstated
• Harmonious co-existence

2. Conduct a debate on ‘Use of artificial plant hormones – problems and possibilities’.

3. Collect information about novel laboratory tests related to diagnosis of diabetes and conduct an exhibition on World Diabetes Day.

Chemical Messages for Homeostasis More Questions and Answers

Question 1.
Correct the sentence if it is wrong
1. Endocrine glands are ductless glands
2. The alpha cells in the Islets of Langerhans secrete insulin.
3. Aldosterone slows down the action of defense cells.
4. Anti Diuretic hormone helps in the reabsorption of water in the kidneys.
5. Hypothalamus secretes inhibitory hormones which stimulate the anterior lobe of the pituitary gland.
Answer:
1. Endocrine glands are ductless glands
2. The beta cells in the islets of Langerhans secrete insulin.
3. Cortisol slows down the action of defense cells.
4. Anti Diuretic hormone helps in the reabsorption of water in the kidneys.
5. Hypothalamus secretes releasing hormones that stimulate the anterior lobe of the pituitary gland.

Question 2.
Endocrine glands are called ductless glands. Why?
Answer:
Endocrine glands do not have particular ducts to carry hormones to various tissues. Hence they are called ductless glands.

Question 3.
Name the hormone-producing centers situated in the brain?
Answer:
Hypothalamus, pituitary, Pineal

Question 4.
The gland which is active only during infancy?
Answer:
Thymus

Question 5.
Though hormones reach every part of the body through the blood, all hormones do not act upon all cell. Explain the reason.
Answer:|
The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the combination of each hormone molecule and its receptor. Following this, enzymes are activated withfn the cell. As a result, certain changes occur in cellular activities.

Question 6.
Name the digestive gland which is also functioning as an endocrine gland?
Answer:
Pancreas

Question 7.
What is the normal level of glucose in blood? How is this level maintained?
Answer:
The normal level of glucose is 70-110 mg/100 ml blood. The level of glucose in blood is maintained by the combined action of insulin and glucagon of the Islets of Langerhans tissues of the pancreas. Insulin, released from the beta cells of Islets of Langerhans, helps to reduce blood sugar by accelerating the process of cellular uptake of glucose and Conversion of glucose in to glycogen. When blood glucose level falls, glucagon, released from the alpha cells of Islets of Langerhans, converts glycogen to glucose and synthesizes glucose from amino acids.

Question 8.
Suppose a person is fasting in a day and takes heavy food on the very next day. How is the level of glucose in his body is maintained in these two days?
Answer:
While fasting glucagon converts glycogen or amino acids into glucose. When taking heavy food insulin enhances cellular uptakes of glucose and converts glucose into glycogen.

Question 9.
Diabetic patients frequently take insulin injections. Give reason?
Answer:
Insulin is helpful to reduce the excess glucose in the blood and to maintain its normal level

Question 10.
If the level of glucose increases one feels hunger, thirsty and fatigue instead of becoming energetic. Give reason?
Answer:
Increasing the level of glucose in blood adversely affects the normal functioning of the cells.

Question 11.
A doctor advised one of his patients to use iodized salt and to include more leafy vegetables and marine items in his diet. What should be reason for this recommendation?
Answer:
To prevent goitre. Deficiency of iodine may cause Goitre, a disorder affects on thyroid gland.

Question 12.
Under secretion of thyroxine: Hypothyroidism
Over secretion of thyroxine: ……………..?
Answer:
Hyperthyroidism

Question 13.
Overproduction, as well as underproduction of the hormone thyroxine, may lead to disorders’. Substantiate.
Answer:
Deficiency of thyroxine (Hypothyroidism) leads to cretinism in infants and myxoedema in adults. Excess production of thyroxine (Hyperthyroidism) leads to a condition, known as the Graves disease.

Question 14.
Persistent hyperthyroidism may leads to ……………. disease characterized by bulging of the eye balls.
Answer:
Graves disease

Question 15.
What is the normal level of calcium in the blood? How is this level maintained?
Answer:
9-11 mg/100 ml blood.
When the level of calcium in blood increases, thyroid gland secretes a hormone named calcitonin. It lowers the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood form the bones. When the level of calcium in blood decreases, parathyroid gland secretes parathormone. It increases blood calcium by reabsorbing it from the kidneys and also preventing the deposition of calcium in bones.

Question 16.
Complete the flow chart

Answer:
A. Medulla
B. Aldosterone
C. Cortisol
D. Norepinephrine

Question 17.
Overproduction of parathormone can weaken the bones. Why?
Answer:
The hormone, parathormone prevents the deposition of calcium in bones resulting its weakening.

Question 18.
The hormone which can be used to prevent allergy and inflammation? Can this hormone be given to diabetic patients? Why?
Answer:
Cortisol of adrenal gland. It cannot be given to diabetic patients as it increases the level of glucose in blood.

Question 19.
The pineal gland is known as the ‘biological clock’ in the body. Why?
Answer:
Melatonin, the secretion of the pineal gland helps to . maintain rhythm of our daily activities. Therefore pineal gland is called as the biological clock.

Qn. 20
What are the hormones of hypothalamus stored in the posterior lobe of pituitary gland? Mention its functions.
Answer:
Oxytocin – Facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall and also facilitates lactation Vasopressin (Anti Diuretic Hormone) – Helps in the reabsorption of water in the kidneys.

Question 21.
Give reasons.
Some times certain pregnant women need to take oxytocin injection.
Answer:
Oxytocin facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall. It also facilitates lactation.

Question 22.
Point out the functions of releasing hormones and inhibitory hormones.
Answer:
Releasing Hormones: Stimulate the anterior lobe of the pituitary to secretes tropic hormones and other hormones.
Inhibitory Hormones: Inhibit the production of tropic hormones and other hormones from the anterior lobe of the pituitary gland.

Question 23.
What is the reason behind the difference in the quantity of urine during summer and rainy season?
Answer:
The production of vasopressin is high during summer season where water loss is excessive through sweat. But its production is less during winter and rainy seasons and there is difference in the quantity of urine during summer and rainy seasons.

Question 24.
Why do Vasopressin is known as antidiuretic hormone (ADH)?
Answer:
Because vasopressin retains the quantity of water by inducing the kidneys to reabsorb it.

Question 25.
Complete the following table related with the hormonal functions of our sex organs.

Answer:

Question 26.
Identify the hormone defects concern with the following hints.
a) Insulin injection
b) Treatment using thyroxine
c) Food and medicine containing calcium
d) Seafood, vegetable and iodized salt.
Answer:
a) Diabetes
b) Myxoedema
c) Osteoporosis
d) Goiter

Question 27.
How is homeostasis of the body maintained?
Answer:
Homeostasis of the body maintained by the combined action of the quick nervous system and the slow endocrine system.

Question 28.
How are pheromones useful to animals?
Answer:
Pheromones help in attracting mates, to inform the availability of food, to determine the path of travel and to inform about dangers.

Question 29.
A farmer says pest control is made possible using pheromones. Can you say how?
Answer:
Artificial pheromones are used for pest control in agricultural field.

Question 30.
Identify the plant hormone that performs the following functions.
a) flowering and growth of leaves
b) ripening of fruits
c) dropping of leaves and fruits
d) growth of terminal bud.
Answer:
a) Gibberellin
b) Ethylene
c) Abscisic acid/ ethylene in excess amount.
d) Auxin

Question 31.
Site examples of situations where artificial plant hormones are applied widely.
Answer:
Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc.
Ethyphon, a chemical which is available in liquid form gets transformed into ethylene when used in rubber trees, and it increases the production of latex.

Auxins: Naphthalene Acetic Acid (NAA), Indol Butyric Acid (IBA) etc. are used for sprouting and the prevention of dropping of premature fruits. 2,4- D (2, 4-Dichloro phenoxy acetic acid) is used as a weedicide.

Gibberellins: Used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist in marketing.

Abscisic acid: As it accelerates the dropping of fruit, it is used for harvesting fruits at the same time.

Question 32.
The following figure shows the relationship of hypothalamus with an endocrine gland. (Model 2016)

a) Write down the name of endocrine gland marked as X
b) Write down the name of hormone produced the A and B.
c) Mention the functions of hormones produced the B.
Answer:
Answer:
a) Pituitary gland
b) A – Tropic hormone
B – Oxytocin and vasopressin
c) Oxytocin helps to contraction of smooth muscles and vasopressin helps in the reabsorption of water in the kidneys.

Question 33.
Artificial hormones should be handled with care. What is your opinion?
Answer:
This statement is correct. Though artificial hormones are useful they should be handled with care as they are chemicals, which may cause health and environmental issues.

Question 34.
…………….. is used for increasing fruit size in grapes and apple.
Answer:
Gibberellins

Question 35.
………….. is a plant hormone, used for harvesting fruits in a field at the same time.
Answer:
Abscisic acid

Question 36.
The quantity of urine excreted by a person in different seasons is given below. Analyse-it and answer the following questions. (Model 2016)

a) Write down the climate B and C
b) Analyse the difference shown in B and C and write down its reasons.
c) Which hormone is responsible for the excretion of excess water through urine.
Answer:
a) B – Rainy season or winter season, C – Summer season
b) In rainy season production of vasopressin is less it decreases the reabsorption of water in the kidneys. So raises the quantity of urine. In summer season production of vasopressin increases. It increases the reabsorption of water in kidneys and lowers the quantity of urine.
c) ADH or vasopressin

Question 37.
Given below is the blood test result of a person. Analyze the result and answer the following questions? (Model 2016)
Glucose – 200mg/100ml
Calcium -11 mg/100ml
a) Name the disease of the man mentioned in the test report.
b) Write down the name of hormone which related to this disease.
c) What is the cause of this disease?
Answer:
a) Diabetes mellitus
b) Insulin
c) It is caused either by the decreased production of insulin or its malfunctioning

Question 38.

a) Complete the table based on the hormone somatotropin (Model 2014)
b) This hormone is not a tropic hormone. Why?
Answer:
a) (i) X-dwarfism 1) become dwarfs due to stunted growth of bones
ii) Y – gigantism 2) Growing tall with a heavy body
iii) Z-acromegaly 3) enlargement of internal organs and thickening of bones, especially in hands feet and face.

b) Somatotropin does not induce any other endocrine gland to release its hormone

Question 39.
The quantity of urine excreted by a person in different seasons is given below. Analyse-it and answer the following questions. (Model 2014)

a) Which is the coldest season?
b) Which hormone is responsible for the variation in quantity of urine?
c) How this hormone regulates water level of the body.
Answer:
a) Season 3
b) ADH/Vasopressin
c) This hormone promotes reabsorption of water from renal tubules when normal level of water in blood decreases. The rate of reabsorption of water in the kidney is decreased when there is no sufficient amount of vasopressin.

Question 40.
Some hormones are given below. Make them into 4 pairs. Give reasons for pairing. (Model 2014)


basis pairing:- Products of same gland

Question 41.
Observe the chart (March 2013)

Write down the climate A and B
Answer:
A-Summer season
B – Rainy season or winter

Question 42.
Changes in the number of hormones produced will affect our bodily activities. Write down the changes occur in our body by the increase and decrease of the hormones given below.
a) Parathormone
b) Vasopressin
Answer:
a) Increase of parathormone – Bones fragile stones in urinary tract, high blood calcium
Decrease of parathormone – Blood calcium level decrease and it leads to tetany

b) Vasopressin
Production of vasopressin increases It accelerate the rate of reabsorption of water from kidney. So the loss of water through urine is reduced.
Production of vasopressin decreased The rate of reabsorption is reduced and more water discharged out through urine.

Question 43.
Rearrange B, C and D according to the data given A

Answer:

Question 44.
“It is now that I understand why the cock crows early in the morning every day”. Anu said this during a classroom discussion on the rhythm of physiological activities.
a) Which is the hormone that regulates such activities?
b) Which gland secretes this hormone.
c) Write down more examples for such activities
Answer:
a) Melatonin
b) Pineal gland
c) It regulates the rhythm of life, reproductive activities of organisms with definite reproductive periods.

Question 45.
Fill up the blanks (Model 2012)

Answer:
a) Thyroxine
b) Thyroid
c) Insulin
d) Diabetes
e) Pituitory gland
f) Dwarfism

Question 46.
Fill up the blanks

Answer:
a) – Gibberellin
b) – Helps in the ripening of fruits
c) – Abscisic acid

Chemical Messages for Homeostasis SCERT Questions and Answers

Question 1.
Observe the illustration given below and explain how hormones act in target cells.

Answer:
The cell which are acted upon by hormones are called target cells. Only cells having specific receptors can receive a particular hormone. A hormone-receptor complex is formed by the . combination of each hormone molecule and its receptor. Following this, enzymes are activated within the cell. As a result, certain changes occur in cellular activities.

Question 2.
Some statements relate to endocrine system are given below. (Question Pool 2017)
A. Hormones are the secretions of endocrine glands.
B. Hormones are transported through lymph.
C. Hormones are transported through blood.
D. All the harmonies produced by the endocrine glands are proteins.
a) Choose the correct statement.
b) Imagine that particular hormone is not entering a particular cell. What may be the reason? Formulate two hypotheses.
Answer:
a) A, C
c) Receptors of that hormone in not in the cell

Question 3.
Examine the graph indicating the blood glucose level of different individuals before breakfast. (Question Pool 2017)

a) Which individual is affected by diabetes mellitus?
b) Write two actions of insulin to prevent the rise in the level of glucose in blood.
c) Why do people having diabetes mellitus experience extreme fatigue?
Answer:
a) (B)
b) 1. Enhances the entry glucose into the cell.
2. Converts glucose to glycogen in liver and muscles.
c) Sufficient quantity of glucose i not reaching the cell. Energy production decreases. Excess amount of glucose is eliminated through urine.

Question 4.
Case sheets of two patients are given below. Analyze them and answer the questions. (Question Pool 2017)

a) Which are the diseases whose symptoms are indicated above?’
b) Write the reasons for the diseases.
Answer:
a) Case -1 cretinism;
Case – 2 graves disease

b) Case -1 reasons
Deficiency of thyroxine during foetal stage and infancy.
Case-2 reasons
1. Persistent hyperthyroidism
2. Excessive production of thyroxine.

Question 5.
Analyse the table given below. Rearrange column Band C according to the indicators in Column A. (Question Pool 2017)

Answer:
1 – (b) – (r)
2 – (c) – (p)
3 – (a) – (q)

Question 6.
Honey bees and termites live in colonies. (Question Pool 2017)
a) Name the chemical substance which helps them to live together.
b) Mention two uses of these chemical substances.
Answer:
a) Pheromones
b) 1. attracting mates
2. informing availability of food
3. determining the path of travel
4. informing the dangers

Question 7.
Observe the diagram and answer the questions. (Question Pool 2017)

a) Which endocrine gland does ‘X’ indicate?
b) Which are the two hormones produced by the gland to control the physical activities with the sympathetic system?
Answer:
a) Adrenal gland
b) Epinephrine, Norepinephrine

Question 8.
Maintenance of the level of calcium in the blood is illustrated below. Analyse-it and answer the following questions. (Question Pool 2017)

a) Name the hormone indicated as X’.
b) Which gland produces the hormone ‘Y’?
c) Write another activity performed by ‘X’ to raise the level of calcium in blood.
Answer:
a) Parathormone
b) Thyroid gland
c) Helps in the reabsorption of calcium from kidneys.

Question 9. (
Observe the diagram of the endocrine gland given below and answer the question. (Question Pool 2017)

a) Name the part indicated as A and B.
b) Name the hormones synthesized by A. Explain their action.
Answer:
a) A Medulla
B Cortex
b) Epinephrine, Norepinephrine
Epinephrine – Helps to tide over emergency situations
Norepinephrine – acts along with epinephrine

Question 10.
An individual loses large quantities of water through urine (Question Pool 2017)
a) Which could be the disease?
b) Analyze the conditions that lead to this disease.
Answer:
a) Diabetes insipidus
b) ADH is synthesized by hypothalamus.
ADH increases the reabsorption of water into the kidney.
Synthesis of ADH decreases.

Question 11.

a) Identify X and Y. (Question Pool 2017)
b) What is the function of ‘Y’?
Answer:
a) Portal vein – X
Posterior lobe of pituitary – Y
b) Stores the hormones vasopressin and oxytocin synthesized by hypothalamus and releases them into blood when required.

Question 12.
Given in the table below is to growth hormone. Complete the table suitably. (Question Pool 2017)

Answer:
a) dwarfism
b) Excessive production of growth hormone during the growth phase.
c) Excessive production of somatotropin after the growth phase.
d) Growth of the bones on face, jaws and fingers.

Question 13.
Given below is a doctor’s comment at a seminar conducted as part of Diabetic day.
“In diabetic patients, the blood glucose level before breakfast is above 126mg/100ml.
Analyse the statement and enlist the reasons.
Answer:

• Decreased production of insulin
• Malfunctioning of insuline
• Destruction of Beta Cells
• Inactive insulin

Question 14.
Given below are a few statements related to hormones. Pick out the correct ones. (Question Pool 2017)
a) Estrogen helps to maintain embryo in the uterus.
b)Progesterone facilitates childbirth.
c) Prolactin helps in the production of milk.
d) Oxytocin n faci itates I a citation.
Answer:
c, d

Question 15.
Analyze the statements given below and write the reason. (Question Pool 2017)
a) Oxytocin is injected in pregnant women during childbirth, (delivery)
b) Feels sleepy during night, wakeup when day breaks.
Answer:
a) Facilitates childbirth by stimulating the contraction of smooth muscles in the uterine wall.
b) When the level of melatonin increases at night, we feel sleepy,
We wake up when the level of melatonin decreases during the day.

Question 16.
Analyse the table and identify the correct pair. (Question Pool 2017)

Answer:
a) Somatotropin decreases during growth phase – dwarfism

Question 17.
Observe the table, re-arrange column Band C according to column A.

Answer:
1 – (b) – (S)
2 – (d) – (P)
3 – (a) – (Q)

Question 18.
A farmer named Balan cultivated oranges in his orchard. Now the trees are full of oranges. The price of oranges is Rs. 80/kg. (Question Pool 2017)
A) This farmer wants to harvest all fruits together.
B) Ripen them together.
a) Suggest two artificial plant hormones to satisfy the A, B needs of the farmer.
b) Uncontrolled use of plant hormones must be controlled. Evaluate this statement.
Answer:
A) a) A – Abscisic acid
B – Ethylene
b) Though artificial hormones are useful they should be handled with care as they are chemicals. Uncontrolled use of it may cause health and environmental issues.

Question 19.
Analyse the indicators and answer the question given below. (Question Pool 2017)
Indicators
Accelerates the growth and development of the brain in the foetal stage and infancy.
a) Which hormone are the indicators about?
b) Construct a flow chart relating the action of hypothalamus and pituitary in the synthesis of this hormone.
Answer:
a) Thyroxine
b)

Question 20.
Artificial plant hormones are used extensively in the agricultural sector. (Question Pool 2017)
Write the name and function of two artificial plants. hormones belonging to the category, auxin.
Answer:
NAA- Sprouting, prevention of premature fall of fruits.
IBA – -do-
2, 4 – D – Weedicide

Question 21.
Artificial plant hormones are used extensively in the agricultural sector. Write a short note on the advantages and disadvantages of these (Question Pool 2017)
Answer:
Advantages:

• Sprouting
• Prevents premature fall of fruits
• Medicinal action
• Increases size of fruits
• Ripening of fruits
• Increases production of latex in rubber trees
• Harvesting fruits at the same time.
• Prevents early ripening of fruits

Disadvantages:

• Environmental issues
• Health issues

Question 22.
Choose the correct statement related to pheromones from those given below. (Question Pool 2017)
a) Pheromones are chemical substances secreted inside the body for communication.
b) This is the message to attract mates, determining the path of travel, etc.
c) Musk in the civet cat is a pheromone.
d) Bombycol is the pheromone secreted by the female silkworm.
Answer:
b, d

Question 23.
Analyze the box given below and complete the table suitably. (Question Pool 2017)

Answer:

Question 24.
Indicators related to the endocrine glands are given below. Analyze them and answer the questions. (Question Pool 2017)
1. Situated just below the sternum.
2. Active during infancy.
But constricts at puberty.
a) Name this endocrine gland?
b) Which is the hormone synthesized by this gland?
c) Write the function of this hormone.
Answer:
a) Thymus gland
b) Thymosin
c) Controls the activities and maturation of lymphocytes which help to impart immunity.

Question 25.
Given below is the illustration showing the hormones synthesized by the anterior lobe of the pituitary gland. Complete it Suitably. (Question Pool 2017)

Answer:
a) Stimulates thyroid gland
b) ACTH
c) Production of milk
d) Enhances growth

Question 26.
Teacher: The TSH hormone synthesized by the pituitary gland acts on the thyroid gland. It is transported to the thyroid gland through blood. All hormones are transported like this through blood. (Question Pool 2017)
Amirtu: Can all the hormones synthesized by the pituitary gland reach the thyroid gland and act there? What is your answer for Ammu’s doubt?
Answer:
Receptors to receive other hormones synthesized by the pituitary gland are absent in the thyroid gland.

Question 27.
Plant hormones and their functions are given in two boxes below. Pair them suitably (Question Pool 2017)

Answer:
(a) – (iv)
(b) – (ii)
(c) – (i)
(d) – (iii)

Question 28.
The problems faced by two farmers are below. Suggest two artificial plant hormones to overcome this. (Question Pool 2017)
Satheesh: Excessive growth of weeds in the agricultural field.
Saneesh: Premature fall of fruit in the mango orchard.
Answer:
Satheesh: 2, 4- D
Saneesh: NAA /IBA

Question 29.
Observe the illustration given below and answer the questions. (Question Pool 2017)

a) Write the names of the hormones ‘X’ and Y\
b) Mention two actions that take place in A and B.
c) Name the gland which synthesises X and Y.
Answer:
a) X-Insulin; Y-Glucagon
b) A-Converts glycogen to glucose
B – Converts glucose to glycogen
c) Pancreas

Question 30.
Identify the word pair relationship and fill in the blanks. (Question Pool 2017)
a) Civet cat:………………
Silkworm: Bombycol
b) Breaks up stored food: Gibberellins
helps in fruit ripening: ……………….
c) Vasopressin: Diabetes insipidus
Insulin: ………………
d) Dwarfism: somatotropin
Myxoedema: ………………..
Answer:
a) Civetone
b) Ethylene
c) Diabetes mellitus
d) Thyroxine

Question 31.
Pick the odd one out. Write the common features of the others. (Question Pool 2017)
a) Increases metabolic rate, increases energy production regulates growth in children, promotes production of milk.
b) Goitre, Acromegaly, Hypothyroidism, Hyperthyroidism.
c) Cortisol, Vasopressin, Epinephrine, Norepinephrine.
d) Ethylene, Cytokinin, Auxin, Pheromones.
Answer:
a) Increases the production of milk: all others are the activities of thyroxine.
b) Acromegaly: All others are disorders/diseases, related to thyroid gland
c) Vasopressin: All others are hormones of adrenal gland
d) Pheromones: All others plant hormones

Question 32.
Choose the correct statement. (Question Pool 2017)
a) Synthesis of vasopressin increases if the level of water in the blood increases.
b) Thyroid-stimulating hormone stimulates the activity of the thyroid gland.
c) Synthesis of insulin increases if the blood glucose level rises.
d) Deficiency of thyroxine causes cretinism in adults.
Answer:
b, c

Question 33.
Maintenance of the level of calcium in blood is illustrated below. Analyse-it and answer the questions. (Question Pool 2017)

a) Which are the hormones indicated as ‘X’, ‘Y’?
b) Write the actions performed by ‘X’ in the bone and ‘Y’ in the kidney.
c) How does the deficiency of ‘Y’ affect the process of blood clotting?
Answer:
a) X – Calcitonin: Y – Parathormone
b) Action of X : Deposits excess calcium in bones.
Action of Y : Reabsorbs calcium into the blood in the kidney.
c) Deficiency of Y decreases the level of calcium in blood.
As calcium is required for blood clotting, the clotting process becomes slow.

Question 34.
Make suitable word pairs from the words given below. (Orukkam – 2017)

Answer:
Vasopressin- Diabetes insipidus
Dwarfism – Somatotropin
Cretinism – Thyroxin

Question 35.
Complete the illustration using the words given in the box. (Orukkam – 2017)

Answer:

Question 36.
Observe the illustration and answer the following questions? (Orukkam – 2017)

a) Identify the parts marked as A , B and C ?
b) Name the hormones indicated as 1, 2, 3, 4 and 5?
c) What are the functions of the hormones Oxytocin and Prolactin?
d) What are the abnormalities caused by the difference in the production rate of the hormone marked as 1?
Answer:
a) A-Anterior lobe of pituitary
B – posterior lobe of pituitary
C – Hypothalamus

b) 1 – Somatotropin /growth hormone
2 – Vasopressin /ADH
3 – Tropic hormones
4, 5 – TSH/ACTH

c) Oxytocin facilitates childbirth by the contrac¬tion of smooth muscles in the uterine wall and also facilitates lactation. Vasopressin helps in the reabsorption of water in the kidney to prevent water loss through urine.

d) Dwarfism, Gigantism and Acromegaly

Question 37.
Identify the word pair relationship and complete the following. (Orukkam – 2017)
a) Alpha cells: Glucagon
Beta Cells: …………….
b) Prolactin: Production of milk
……………….: Facilitate lactation
c) Parathyroid: Parathormone
Thyroid
Answer:
a) Insulin
b) Oxytocin
c) Calcitonin

Question 38.
All hormones are being transported through the blood and reach all cells of the body, but all hormones are not functioning in all cells. Why? (Orukkam – 2017)
Answer:
Each hormone act only its target tissue, where spe¬cific receptors present to accept the same hormone.

Question 39.
The increased or decreased level of thyroxin may disrupt the homeostasis of the body. Explain? (Orukkam – 2017)
Answer;
Due to hypothyroidism (eg. cretinism) low metabolic rate, sluggishness, sleeplessness, increase in body weight, hypertension, oedema, etc.
Due to hyperthyroidism (eg. Graves disease) high metabolic rate, increased heartbeat, rise in body tem¬perature, sweating, sleeplessness, loss of weight, emotional imbalance.

Question 40.
Bees and termites are maintaining the colony life by using some chemical substances as chemical messages. (Orukkam – 2017)
a) What are these chemical substances?
b) Write the other uses of these chemical substances?
c) Give other examples for these chemical substances?
Answer:
a) Pheromones
b) To attract mates, to inform about food or dangers, to live in colonies, to follow one afterthe other.
c) Civetone in civet cat, Bombycol in female silkworm moth.