Plus Two Chemistry Model Question Paper 2

Kerala Plus Two Chemistry Model Question Paper 2

Time: 2 Hours
Cool off time: 15 Minutes
Maximum: 60 Scores

General Instructions to candidates

• There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hrs.
• Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
• Read questions carefully before you answering.
• Read the instructions carefully.
• Calculations, figures, and graphs should be shown in the answer sheet itself.
• Malayalam version of the questions is also provided.
• Give equations wherever necessary.
• Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

(Questions 1 to 7): Carry one score each. Answer all questions.

Question 1.
Which type of stoichiometric defect am I shown by AgCI?

Question 2.
What is the two-dimensional coordination; a number of a molecule in a square close-packed later?

Question 3.
Mercury is a ……… cell.

Question 4.
For the reaction ; Cl₂ (g) + 2NO(g) → 2NOCI(g) ; the rate law is expressed as rate = K[CI₂][NO]² ! What is the overall order of this reaction?

Question 5.
Name the method used for removing gangue I from sulfide ore.

Question 6.
Which one of the following compound reacts, with chlorobenzene to produce DDT?

Question 7.
Biotin is an organic compound present in yeast deficiency in the diet causes dermatitis 1 and paralysis. It is also known as

a. Vitamin H
b. Vitamin B₃
c. Vitamin B₁₂
d. VitaminD

(Questions 8 to 20) : Answer any ten. Each question carries two scores.

Question 8.
i. Which of the following is a molecular solid?
a. Diamond
b. Graphite
c. Ice
d. Quartz
ii. Unit cells can be classified into primitive and centered unit cells. Differentiate between primitive and centered unit cells

Question 9.
i. Which of the following is a secondary cell?
a. Dry cell
b. Leclanche cell
c. Mercury cell
d. None of these
ii. What is the relationship between resistance and conductance?

Question 10.
Complete the following.

Question 11.
Match the items of Column I with items of Column II.


Question 12.
How will you convert propanoic acid into the following compounds?
i. Ethane 0
ii. Butane

Question 13.
Haloalkanes and haloarenes react with metals to give hydrocarbons or products from which hydrocarbons are obtained easily.

Identify the product and name the reaction.

Identify the product and name the reaction.

Question 14.
Most of the organic chlorides, bromides and iodides react with certain metals to give compounds containing carbon-metal bonds.
i. Give one example of such a compound.
ii. How will you prepare the above compound?

Question 15.
Schematic alignment of magnetic moments of ferromagnetic, antiferromagnetic and ferrimagnetic substances are given below. Identify each of them.

Question 16.
Aldehydes and ketones are organic compounds containing a carbonyl group.
i. Write a chemical reaction to distinguish between aldehydes and ketones.
ii. Aldehydes and ketones can be subjected to Clemmensen reduction and wolfishness reduction. Name the reagents used in both cases.

Question 17.
Write any two electrophilic substitution reactions of chlorobenzene.

Question 18.
a. Which of the ones mentioned in the above table can be concentrated by magnetic separation. justify your answer.
b. Identify the ones that can be concentrated by leaching.

Question 19.
The temperature dependence of the rate of a chemical reaction can be accurately explained by Arrhenius equation. With the help of the Arrhenius equation calculate the rate constant for the first order reaction, C₂ H₅ I_(g) → C₂ H_4(g) + HI_(g) at 700 K. Energy of activation (E_a) for the reaction is 209 KJmof1 and rate constant at 600 K is 1.60 x 105 S’1. [Universal gas constant R= 8.314K1mol’1].

Question 20.
Chemotherapy is a term found in medical terminology. What is chemotherapy?

(Questions 21 to 29): Answer any seven. Each questions carries three scores.

Question 21.
a. The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid is termed adsorption.
i. What is adsorption isotherm?
ii. Write the mathematical expression of Freundlich adsorption isotherm.
b. Enzymes are known as biochemical catalysts. Write any two important characteristics of enzyme catalysis.

Question 22.
Biomolecules are formed by certain specific linkages between simple monomeric units. Write the names of linkages and monomeric units in the following class of biomolecules.
i. Starch
ii. Protein
iii. Nucleic acid

Question 23.
Polymers are macromolecules formed by a union of monomers.
a. Name natural polymer and synthetic polymer.
b. Distinguish between thermoplastic and thermosetting polymers with an example.

Question 24.
Carbohydrates are broadly divided into monosaccharides, oligosaccharides, and polysaccharides.
a. Write one example each of monosaccharide and oligosaccharide.
b. i. Write any one method for the preparation of glucose.
ii. What is peptide linkage?

Question 25.
a. Amines are basic in nature. Arrange the following compounds in the increasing order of their basic strength.
NH₂, C₆H₅NH₂, CH₃ NH₂, (CH₃) 2NH, (CH₃)₃N.
b. How will you convert Toluene (C₆H₅CH₃) to Benzaldehyde

Question 26.
Consider the coordination compound [CO(NH₃)₅ SO₄]Br.
a. Write the IUPAC name of the above compound.
b. What is the primary valence and secondary valence of the central metal, Cobalt, in the above coordination compound?
c. Which type of structural isomerism is exhibited by the above coordination compound?

Question 27.
Different drugs have different therapeutic action in our body. Write the therapeutic action of the following drugs in our body.
a. Tranquilizers
b. Analgesics
c. Antibiotics

Question 28.
The concept of AG° of coupled reactions f is used to explain reductions in metallurgy.
a. Explain the above statement?
b. In the blast furnace for manufacturing iron, most of the reduction is carried out by CO rather than C (coke). How can you account for this?

Question 29.
a. LDPE is a homopolymer, while Nylon66 is a copolymer. Explain?
b. Classify the following into homopolymer or copolymers. Nylon-66 and HDPE

(Questions 30 to 33): Answer any three. Each questions carries four scores.

Question 30.
Detergents are used to remove oil and dirt from surfaces.
a. What are synthetic detergents? Give an example.
b. What are anionic, cationic and nonionic detergents? Illustrate with examples?
c. A synthetic detergent is used as a dishwasher. To which of the above type would it belong?

Question 31.
Crystal defects give rise to certain special properties in the solids.
a. What is meant by Frenkel defect?
b. VWiy does Li Cl not exhibit Frenkel defect?
c. Explain the pink color of LiCI when heated in the vapors of Li.

Question 32.
The hydrolysis of an ester in acid medium is a first order reaction.
a. What do you mean by an Ist order reaction?
b. What is the relation between the rate of the instant and half-life period of a reaction?
c. Half-life period of a first-order reaction is 20 seconds. How much time will it take to complete 90% of the reaction?

Question 33.
The limiting molar conductivity of an electrolyte is obtained by adding the limiting molar conductivities of cation and anion of the. electrolyte.
a. Name the above law.
b. What is meant by limiting molar conductivity?
c. Explain how conductivity measurements help to determine the ionization constant of a weak electrolyte like acetic add.
d. Explain the change of conductivity and molar conductivity of a solution with dilution?

Answers

Answer 1.
Frenkel defect

Answer 2.
4

Answer 3.
Primary cell

Answer 4.
3

Answer 5.
Froth flotation process

Answer 6.
d

Answer 7.
a

Answer 8.
i. c. Ice I
ii. In primitive unit cells, constituent particles are present only on the corner position I of unit cell whereas in centered unit cell, one or more constituent particles are present at a position other than corners in addition to those at corners.

Answer 9.
i. d. None of these
ii. Conductance (C) is the reciprocal of the resistance (R). C = 1/R

Answer 10.

Answer 11.

Answer 12.

ii. Kolbe’s electrolysis: By the electrolysis of aqueous solution of sodium salt of the propanoic acid.

Butane is formed at the anode.

Answer 13.

Answer 14.
i. Grignard reagent -R MgX
ii. The alkyl halide is treated with magnesium in dry ether to get Grignard reagents.

Answer 15.
i. Antiferromagnetic.
ii. Ferrimagnetic.
iii. Ferromagnetic.

Answer 16.
i. Oxidation: Aldehydes on oxidation give carboxylic acid containing same no. of C atoms.

Ketones on oxidation give a mixture of carboxylic acids containing lesser no.of carbon atoms.

ii. Zn amalgam and HCI for Clemmensen reduction. Hydrazine heated with KOH in ethylene glycol for WolfKishner reduction.

Answer 17.

Answer 18.
a. Haematite, magnetite , Iron pyrites,
b. Bauxite.

Answer 19.
K = ln A – \(\frac { { E }_{ a } }{ RT }\);
where K = Rate constant,
A = Arrhenius factor, E_a = Activation energy, T= Temperature, R = Gas constant

Answer 20.
i. Use of chemicals for therapeutic effect is called chemotherapy.

Answer 21.
a. i. The variation in the amount of gas adsorbed by the adsorbent with pressure at constant temperature is expressed using a curve called adsorption isotherm.
ii. \(\frac { X }{ m } =k.{ p }^{ 1/2 },n>1;\)
where x/m is the extent of adsorption, P is the pressure, K and n are constants which depend on the nature of the adsorbent and the gas at a particular temperature.
b. i. Most highly efficient. One molecule of an enzyme may transform one million molecules of the reactant per minute.
ii. Highly specific in nature. Each enzyme is specific for a given reaction.

Answer 22.
i. α – D- glucose, the bond is glycosidic linkage.
ii. An amino acid, a peptide bond is a linkage.
iii. Nucleotide, Bond is a hydrogen bond.

Answer 23.
a. Natural polymer Cellulose, Starch Synthetic polymer PVC, Nylon,
b. Thermoplastics are linear or slightly branched long chain molecules, which can be remolded again and again by heating and cooling. The intermolecular force is intermediate between elastomers and fibers.

Thermosetting are cross-linked or heavily branched molecules. On heating, they undergo extensive cross-links and becomes infusible. They cannot be remolded.

Answer 24.
a. Monosaccharide Glucose, Fructose-Oligosaccharide Maltose, Lactose, Sucrose Polysaccharide Cellulose
b.
i. Starch.

ii. The linkage between units of amino acids in a polypeptide linkage is called peptide linkage.

Answer 25.

Answer 26.
a. Pentaamminesulphatocobait (III) bromide.
b. Primary valence is 3 and secondary valence is 6.
c. Ionization isomerism.

Answer 27.
a. Tranquilizers are used for the treatment of stress and mental diseases.
b. Analgesics reduce pain without causing any disturbance to the nervous system.
c. Antibiotics are drugs used to treat infections in our body. It inhibits the growth of microorganisms.

Answer 28.
a. For the feasibility of a reaction, ΔrG° must be negative. The positive value of ArG° means that the reaction is not spontaneous. This reaction can be made spontaneous by coupling with a reaction having very large ve Gibb’s energy value so that Gibb’s energy for the two combined reactions become ve.
b. A better reducing agent should have a larger ve value for AG°. If coke is used ArG° = 13 KJ/mol and for CO, ArG° = 56.2 KJ/mol Comparing the two values, it is clear that CO is a better reducing agent than C.

Answer 29.
a. If the polymer is formed only one type of monomer units, then it is a homopolymer. LDPE is low-density polyethylene whose monomer is ethylene. Hence it is a homopolymer.
Nylon66 is the polymer containing two different monomer units hexamethylene diamine and adipic acid. Hence it is a copolymer.
b. Nylon6: Homopolymer HDPE: Homopolymer

Answer 30.
a. Synthetic detergents are cleansing agents which have all the properties of soap, but actually, do not contain any soap. They can be used both in soft and hard water.
b.
i. Cationic detergents are quarternary ammonium salts of amines with acetates, Cl or Bras anions. Cationic part posses a long hydrocarbon chain. They are expensive and have germicidal properties used in hair conditioners, eg., Cetyl trimethyl ammonium bromide.
ii. Anionic detergents are sodium salts of sulfonated long chain alcohols or hydrocarbons. The anionic part of the molecule is involved in cleaning action. Used in toothpaste, household work, eg., sodium dodecyl benzene sulphonate.
iii. Nonionic detergents do not contain any ion. eg., Detergent formed by stearic acid and polyethylene glycol. Liquid dishwashing detergents are nonionic.
c. It belongs to a nonionic type.

Answer 31.
a. Frenkel defect arises due to the dislocation of a cation from its normal site to an interstitial site.
b. Frenkel defect is shown by crystals with a large difference in size between the anion and cation. In LiCI, the cation and anion have comparable (similar) size. So it will not exhibit Frenkel defect.
c. This is due to metal excess defect due to anionic vacancies. When LiCI is heated in vapors of Li, the Cf ions diffuse to the surface of the crystal creating vacant sites. Instead, the electrons diffuse into the crystal and occupy these anionic sites, forming F centers. These electrons absorb energy from white light and show a pink color.

Answer 32.
a. If the sum of powers of the concentration terms in the rate expression is one, then the reaction is a first order reaction.

Answer 33.
a. Kohlrausch’s law.
b. It is the molar conductivity of electrolytes at zero concentration or at infinite dilution.
c. The degree of dissociation can be determined by the equation, \(\alpha =\frac { { \lambda }_{ m } }{ { \lambda }_{ 0 }^{ m } }\) To obtain ionisation constant, K_a substitute α in the following equation, \({ K }_{ a }=\frac { { C\alpha }^{ 2 } }{ (1-\alpha ) }\) where C is the concentration a of acetic acid in moles/liter.
d. The conductivity of a solution decreases with a decrease in concentration as the number of ions presents per unit volume of the solution actually decreases. The molar conductivity of electrolytes increases with a decrease in concentration.

Plus Two Chemistry Previous Year Question Papers and Answers