# Kerala Syllabus 10th Standard Chemistry Solutions Chapter 4 Production of Metals

## Kerala State Syllabus 10th Standard Chemistry Solutions Chapter 4 Production of Metals

### Production of Metals Text Book Questions and Answers

→ All ores are minerals, but are all minerals ores?
NO

→ Which metal’s ore is calamine?
Zinc (Zn)

→ Which is the ore of aluminum?
Bauxite (Al2O2 2H2O)

→ Which metals have sulfide ores?
Copper, Zinc

Production Of Metals Class 10 Kerala Syllabus Text Book Page No: 65

→ Complete the table 4.2.

→ Write suitable method of concentration for the ores given in the Table (4.3)

Sslc Chemistry Chapter 4 Kerala Syllabus Text Book Page No: 67

→ Complete The table 4.4

→ Haematite, magnetite, iron pyrites, etc. are the minerals of iron. Which are the ores of iron among these minerals?
Haematite, magnetite.

Chemistry Class 10 Chapter 4 Kerala Syllabus Text Book Page No: 69

→ Complete the table 4.5.

→ Which alloy steel is used for the production of heating coils? Explain the reason.
Nichrome, because of high resistance, easily it becomes hot.

→ Even though nichrome and stainless steel contain the same components they possess different properties. Find out the reason.
The ratio of the component elements are different.

→ Which alloy steel is used for making permanent magnets?
Alnico

Sslc Chemistry Chapter 4 Notes Kerala Syllabus Text Book Page No: 70

→ Complete the table 4.7

→ How ¡s alumina obtained from this aluminum hydroxide?
The precipitate is separated, washed and then heated strongly to get alumina.

Production Of Metals Class 10 Notes Kerala Syllabus Text Book Page No: 71

→ Complete the flow diagram, related to concentration of bauxite, which is given below.

→ Complete the chemical equation for the reaction taking place when Aluminium hydroxide is heated.
Ans. 2Al(OH)3 → Al2O3 + 3H2O

→ Which method can be used for separating aluminum from alumina?
Electrolysis

→ Can we use carbon as the reducing agent? Why?
Can’t use carbon as the reducing agent, because the reactivity of aluminum is very high hence they require very strong reducing agent.

Sslc Chemistry Chapter 4 Notes Pdf Kerala Syllabus Text Book Page No: 72

→ To which electrode does Al3+ move?
Towards negative electrode (Cathode)

Towards positive electrode (Anode)

→ Complete the table related to the electrolysis of Alumina.

### Production of Metals Let Us Assess

Sslc Chemistry Chapter 4 Notes English Medium Question 1.
Which of the properties of metals is utilized in the following instances?
a. Aluminum utensils are used for cooking.
b. Copper is used for making vessels.
c. Gold wires are used in ornaments.
a. Heat conductivity, lightweight, can be molded in any shape, low price, etc.
b. Malleability
c. Ductility

Sslc Chemistry 4th Chapter Kerala Syllabus Question 2.
What are the factors to be considered while selecting minerals for the extraction of metals?
High availability
Extraction of metal should be easy
The percentage of metal content in the mineral should be comparatively high.
Cost of production should below.

Kerala Syllabus 10th Standard Chemistry Chapter 4 Question 3.
Write the different stages involved in metallurgy.
a. Concentration of the ore methods are:

• Levigation/hydraulic washing
• Froth floatation
• Magnetic separation
• Leaching

b. Extraction of metal from the concentrated ore has 2 stages.

• Conversion of ore into its oxide. The different methods are Calcination, Roasting etc.
• Reduction of oxidised ore using suit-‘ able reducing agents.

c. Refining of metals. Different methods are:

• Liquation
• Distillation
• Electrolytic refining

Production Of Metals Class 10 Notes Pdf Kerala Syllabus Question 4.
What are the different methods for the refining of metals?

• Liquation
• Distillation
• Electrolytic refining

Chemistry Chapter 4 Class 10 Kerala Syllabus Question 5.
How is iron extracted industrially?
The ore is crushed into small lumps and then wash out the soluble impurities in running water. Then it undergoes roasting. Thus impurities like sulfur, arsenic, moisture, etc. get removed. The roasted ore is mixed with coke and limestone and the mixture is changed into a blast furnace.
Reaction in blast furnace:

At high temperature, CaCO3 (limestone) decomposes to form CaO.
CaCO2 (s) → CaO(s) + CO2 (g)

This CaO combines with acidic gangue, SiO2 forming slag.
CaO(s)+ SiO2(g) → CaSiO3 (s)

Coke reacts with oxygen and form CO2
C(s) + O2(g) → CO2(g)

CO2 combines with more carbon and produces CO.
CO2(g) + C2(s) + Heat → 2 CO (g)
This CO acts as reducing agent.

Fe2O3 is reduced to form Fe.
Fe2O3(s)+ 3 CO(g) → 2Fe(s)+ 3CO2(g)

Hss Live Guru 10th Chemistry Kerala Syllabus Question 6.
Write the uses of the following:
a. Nichrome
b. Stainless steel
c. Alnico
a. Nichrome – For making heating coils
b. Stainless steel – For the manufacture of utensils, parts of vehicles
c. Alnico-To make permanent magnets

Kerala Syllabus 10th Standard Chemistry Guide Question 7.
Explain the process of producing alumina from bauxite.
Bauxite is treated with hot concentrated NaOH. Aluminum oxide reacts with NaOH solution forming sodium aluminate solution (NaAlO2). The unreacted impurities are removed from the solution. To the remaining solution of sodium aluminate, add Al(OH)3 in small quantity and dilute with water. Then the whole aluminum in the solution gets precipitated as Al(OH)3. The Al(OH)3 precipitated is separated from the solution. Then it is washed and heated strongly. Then Al(OH)3 decomposes to give pure AL2O3 or alumina.

2Al(OH)3(s)→ Al2O3(s) + 3H2O(1).

Hsslive Chemistry Class 10 Kerala Syllabus Question 8.
Explain the method of obtaining pure aluminum from alumina by electrolysis. In this process, the carbon rods are replaced from time to time. Why?
Pure Al2O3 mixed with cryolite undergo electrolysis.

At cathode :
Al2+ + 3e → Al
At anode :
2O2 → O2 + 4e
Carbon at anode reacts with O2and form CO2. Thus anode gets used up. So anode is replaced frequently.

### Production of Metals Extended Activities

Hss Live Guru Class 10 Chemistry Kerala Syllabus Question 1.
You know that metals can be separated from molten compounds of metals by electrolysis. Find out how metals like Na, Ca and Mg are extracted.
Na
Produced by the electrolysis of molten NaCl. KCl is added to reduce the melting point of NaCl.

Chemical equation:
NaCl → Na++Cl-
At cathode : Na++ le → Na
At anode : 2Cl → Cl2 + 2e

Ca:
Mixture of CaCl2 and 16% CaF2 are melted and undergo electrolysis.

Mg:
By the electrolysis of molten mixture of camalite (KCl.MgCl2.6H2O) and NaCl in equal amounts.

### Production of Metals Orukkam Questions and Answers

Hss Live Guru 10th Chemistry Malayalam Medium Question 1.
Complete the table

Chemistry Solutions Class 10 Kerala Syllabus Question2.
Features of ore and impurity are given in the table. Write down the method used for the separation of the ore.

a. How can we convert ore into its oxide form? Explain with proper examples
b. ZnCO3/Cu2S in these two calcination is used for ………. and Roasting is used for ………..
c. Give Examples for reducing agents for reducing oxide ores.
d. Strongest reduction agent
e. Which reducing agent used fur reducing ZnO, Fe2O3, Al2O3 ?
i. Levigation/Hydraulic washing
ii. Magnetic Separation
iii. Froth Floatation
iv. Leaching

a. Calcination
Calcination is the process of heating the concentrated ore at a temperature below its melting point to remove the volatile impurities. When subjected to calcination, impurities like water, organic matter, and other volatile impurities are expelled from the ore. Metal Carbonate and hydroxides decompose to form oxides,
eg: ZnCO is converted to ZnO by calcination

Roasting:
Roasting is the process of heating the concentrated ore at a temperature below its melting point in a current of air. During roasting the ore gets converted into its oxide. When the concentrated ore is subjected to roasting, the water present in it is removed as vapor. Other impurities like sulfur, phosphorus and organic matter are oxidized and expelled. The sulfide combines with oxygen to form oxide eg: Cu2S ore is converted to Cu2O by roasting;
b. Calcination – ZnCO3, Roasting – Cu2S
c. Carbon monoxide, Carbon, Electricity
d. Electricity
e. Carbon Monoxide is used as the reducing agent to extract iron from haematite. (Fe2O3)
ZnO :- Carbon is used as the reducing agent to extract Zinc from Zinc Oxide. Electricity is used to extract aluminum from Al2O3.

Kerala Syllabus Class 10 Chemistry Solutions Question 3.
Complete the table:

a. Low Melting point.
b. Low Boiling points
c. Metals having high electropositivity

Question 4.
a. Complete the table.

b. Stainless steel and Nichrome are having same content (Fe, Ni, Cr, C). But nature of both alloys are different Why?

c. Bauxite and clay are minerals of aluminum. But bauxite is the only ore of Aluminium. Why?.
i. Obtained from Blast Furnace Contains 4% Carbon and other impurities like manganese silicon, phosphorus, etc.

ii. Pig iron mixed with scrap iron and coke melted in a special furnace contains 3% carbon.

iii. Made by purifying cast Iron.

iv. Prepared by varying the amount of carbon from 0.1 to 1.5%.

b. Stainless steel and Nichrome are having the same content but the nature of both alloys are different because ratio of constituent elements are different.

c. A mineral from which a metal is economically, easily and quickly extracted is called the core of the metal. Among the minerals of aluminum, bauxite possesses these properties. Hence bauxite is the ore of Aluminium. Since clay does not possess these properties it is not an ore of Aluminium.

Question 5.
Given below are the equations for the reaction taking place inside the blast furnace.
C + O2→ CO2
CO2+ C → 2CO
CaCO3 + SiO2 → CaSiO3
Fe2O3+3CO → 2Fe + 3CO2
a. Name the ore of iron.
b. Which is the gangue in iron ore?
c. Name the flux used in blast furnace,
d. Gangue + flux → ………… Which product is formed in blast furnace?
e. Reducing agent used in blast furnace.
f. Subjects dropped in blast furnace are …………., …………….
a. Haematite
b. SiO2
c. CaO
d. slag(CaSiO3 )
e. Carbon monoxide
f. A mixture of roasted haematite, coke and limestone.

Question 6.
a. Write down the names of Anode, Cathode, Electrolyte used in the Electrolyte cell for the manufacturing of copper,
b. Write down the equations for the reaction in anode and cathode.
Anode – Copper to be refined
Cathode – Pure Copper
Electrolyte – Aqueous Copper Sulphate Solution mixed with H2SO4

b. Anode – Cu → Cu2 + 2e
Cathode – Cu2+ +2e → Cu

Question 7.
Manufacturing of iron.
a. Name the furnace used for producing iron.
b. Name the materials using for producing iron.
c. Write down the reaction occurring on coke when hot is blasted on it?
d. Why CaCO3 is dropping inside the furnace?
e. Write down the nature of gangue with iron ore.
f. Gangue + flux → ……….. Write down the uses of the product formed in blast furnace.
g. Reducing agent in blast furnace
h. Write down the reactions taking place inside the blast furnace.
i. Iron formed from the blast furnace is called ……………
j. How can we change iron into steel?
k. What are the different types of steel?
a. Blast Furnace
b. Mixture of roasted haematite, coke and limestone.
c. At the bottom of the blast furnace, coke combines with oxygen in the hot current of air. The CO2 which rises up along with the hot air current is reduced by coke.
d. CaCO3 in the furnace decomposes to form CaO and CO2. CaO which is basic combines with SiO2 (acidic) to form slag. Molten slag which is lighter floats over the heavier molten iron. CaCO3 is added to the furnace for the production of slag.
e. Acidic
f. Slag. (CaSiO3) used for the production of cement and in the Construction of Road.
g. Carbon monoxide
h. CaCO3(s) → CaO + CO2
CaO+SiO2 → CaSiO3
C+O2 CO2 + Heat
CO2(g) + C(s) + Heat → 2CO (g)
Fe2O3+3CO → 2Fe + 3CO2
i. Pig iron
j. Different types of steel can be prepared by varying the amount of carbon from 0.1 to 1.5
k. Mild steel, Medium steel, High carbon steel
Mild steel:- If the carbon content in steel is from 0.05% to 0.2 % then it in called mild steel. I

Medium steel :- Medium steel contains carbon from 0.2 % to 0.6 % medium steel

High carbon steel: – If the content of carbon is from 0.61 % to 15 % then it is known as high carbon steel.

Question 8.
Flow chart of Manufacturing Aluminium.

a. Draw the Electrolyte cell and then write answers for the following questions.
b. Anode, Cathode in this cell are …………….
c. Write down the reactions taking place in Anode and Cathode.
d Why Carbon power dropped above the electrolyte?
e. Which gas is evolved out from graphite.
f. Uses of Cryolite.
a.

b. Anode – Carbon Rod, Cathode – Carbon lining
c. Anode -2O2– → O2 + 4e-
Cathode – AI3+ +3e → AI
d. To prevent the chemical reaction of carbon rods with the oxygen in atmosphere.
e. Oxygen
f Cryolite is added to alumina to reduce its melting point and increase its electrical conductivity.

### Production of Metals SCERT Questions and Answers

Question 1.
Nature of some ores are given. Pick ore concentration from the bracket.
(Magnetic Separation, Froth Floatation, Levigation, Leaching)
i. Ores are lighter and impurities are heavier.
ii. Ore is magnetic. But impurities are non-magnetic.
iii. Uses a solution which dissolves the ore.
iv. Ore is heavier and impurities are lighter.
i. Froth floatation
ii. Magnetic separation
iii. Leaching
iv. Levigation

Question 2.
Some metals and ores are given. Match them suitably

Question 3.
Calcination is used to convert zinc carbonate into zinc oxide. But cuprous sulfate is converted into cuprous oxide by roasting.
a. What is the difference between calcination and roasting?
b. What happens to the ore when it is subjected to calcination?
a. Calcination: It is the process in which the ore is heated in the absence of air at a temperature below its melting point so that the moisture content of ore, volatile impurities, bio substances, etc. can be removed. Along with this, metal carbonates and hydroxides are converted into its oxide.

Roasting: It is the process in which the ore is heated in the presence of air at a temperature below its melting point so that the moisture content of ore, sulfur, phosphorous, etc, are converted into its oxide and can be removed. Sulfide ores also get converted into oxides.

b. Zinc carbonate ore is converted to Zinc oxide.

Question 4.
a. Some metals and their methods of concentration are given. Match them suitably.
Liquation, Electrolytic refining, Distillation
b. Write the reason for selecting the methods for the concentration of mercury and tin.
Electrolytic refining – Copper Distillation – Mercury, Zinc
b. Boiling point of mercury is low. Melting point of Tin is low

Question 5.
The order the reactivity of some metals are given. Answer the following questions by analyzing it.
Al >Zn >Cu >Au
a Which metal is produced bytfie electrolysis of its molten salt ?
b. Metal occur in free state in nature,
c. Metal produced by the self oxidation reduction reaction.
d. Metal ore which is reduced by carbon.
a. Al
b. Au
c. Cu
d. Zn

Question 6.
A reducing agent is required to extract the metal from its ore. Why ? Explain with ex ample.
In ores metals are in positive oxidation state, reducing agent is needed (electron giving substance) to get the metal.
Eg: Carbon is used to extract zinc from zincoxide. Zno(s) + C(s) → Zn(s) + CO(g)

Question 7.
The equations of the production of iron in the blast furnace are given. Answer the following questions.
C + O2 → CO2
CO2 + C → 2CO
CaCO3 → CaO + CO2
CaO + SiO2 → CaSiO3
Fe2O3+3CO → 2Fe + 3CO2
a. Which substance reduces haematite in the metallurgy of iron? How this reducing agent is produced in the furnace?
b. Which is the main impurity found in haematite? Which substance is used to remove the gangue?
c. Write the chemical equation of the formation of slag in blast furnace.
a. CO, Oxygen in the blast of hot air reacts with coke, to form CO2. This CO2 again reacts with coke to produce CO.
b. SiO2 – Impurity; CaO – remove gangue
c. CaO + SiO2 → CaSiO3

Question 8.
a. How pig iron is converted into cast iron?
b. Molten cast iron is poured into moulds to make different shapes. Which speciality if cast iron is based for it?
a. Pig Iron mixed with scrap iron and coke, is melted in a special furnace to make cast iron.
b. Molten cast iron expands a little on solidifiation.

Question 9.
Alloys containing iron are given. Find out a, b, c and

a. Fe, Ni, Al, Co
b. For the manufacture of permanent magnets
c. Stainless steel
d. For making heating coils

Question 10.
Aluminium is prepared industrially by Hall-Heroult process. Various steps in the concentration of ore are given below. Write them
in the correct order.
i. The precipitate formed is separated, washed and strongly heated to get alumina,
ii. Crushed bauxite is leached with hot sodium hydroxide solution.
iii. Impurities are removed from the sodium aluminate solution by filtration.
iv. Solution is diluted after adding a little aluminium hydroxide, to precipitate aluminum hydroxide.
Order:
(ii),
(iii),
(iv),
(i)

Question 11.
a. Carbon monoxide cannot be used as reducing agent to extract aluminium from alumina. Why?
b. The electrolytic cell for alumina is given below.

i. Al2O3 dissolved in molten cryolite is used as the electrolyte. What is the purpose of adding cryolite to alumina?
ii. Anode is replaced from time to time while producing aluminium. Why?
iii. Write the chemical equation of the reaction at the cathode.
a. Aluminium compounds are very stable,
b. i. The melting point of alumina is very high. Cryolite is added to alumina to reduce its melting point and increase its electrical conductivity, .
ii. Oxygen liberated at the anode reacts with carbon, forming CO
iii. Al3+ + 3e → Al

Question 12.
a. Illustrate the arrangement of refining copper and label the anode, cathode and electrolyte.
b. Write the chemical equations at the anode and cathode and sustain it as a redox reaction.

As oxidation and reduction takes place it is a redox reaction

Question 13.
Clay, cryolite and bauxite are the minerals of aluminium.
a. Which among them is the ore of aluminium? What is its chemical formula?
b. What are the features of an ore?
a. Bauxite, Al2O3, 2H2O
b. 1. Easily available
2. Metal can be separated easily
3. High content of metal

Question 14.
The chemical reaction of calcium carbonate while heating is given. .
$$\mathrm{CaCO}_{2} \stackrel{\text { Heat }}{\longrightarrow} \mathrm{CaO}+\mathrm{CO}_{2}$$
How the reaction is made use in the metallurgy of iron?
CaO is framed by the decomposition of Ca- CO3. This CaO acts as a flux and combines with SiO2 (gangue) to form CaSiO3 (Slag).

Question 15.
Find the relation and answer the following.
a. Zinc Sulphate : Roasting,
Calcium Carbonate:…………
b. Haematite: Magnetic Separation;
Bauxite:…………..
a. Calcination
b. Leaching

Question 16.
The flowchart of the process of concentrate of aluminium ore is given. Complete the flowchart.

a. NaAlO2(Sodium aluminate)
b. Al(OH)3 /Aluminum hydroxide)
c. The precipitate is separated, washed well and strongly heated;
d. Al2O3

### Production of Metals Exam Oriented Questions and Answers

Very Short Answer Type Questions (Score 1)

Question 1.
What is the importance of adding cryolite in the electrolysis of alumina? ‘
Alumina has a very high melting point. Cryolite lowers the melting point of alumina and improves the conductivity of alumina.

Question 2.
What are gangue, flux and slag?
Gangue: Impurities in the metal ore 1
Flux: Chemical substances used to convert impurities which are not easily removable (gangue) into slag.
Slag: substances which are easily removable when gangue and flux are combined.

Short Answer Type Questions (Score 2)

Question 3.

a. Choose the ore from those given below which can be used in the above figure. Bauxite, Tin stone, Copper pyrites, Calamine
a. Tin stone (SnO2)
b. This figure depicts magnetic separation. SnO2 is a magnetic ore. But the gangue, iron tungstate present in this also has magnetic property.

Question 4.
Haematite, the ore of iron undergo roasting.
a. Which impurity is not removed by this method?
b. How is it removed then? Explain.
a. Silicon dioxide (SiO2)
b. It is removed during metallurgy. At high temperature, CaC03 (limestone) decomposes to form CaO, which is the flux. CaO combines with SiO2 and forms CaSiO3 (slag).
CaCO3(s) → CaO(s) + CO2(g)
CaO(s) + SiO2(s) → CaSiO3(s)

Question 5.
During the concentration process of bauxite,
a. Why is hot concentrated NaOH used?
b. Why isAl(OH)3 added in small quantity and diluted with water to sodium aluminate solution?
a. Only bauxite is soluble in hot concentrated-. ted NaOH. As the impurities are insoluble, they can be easily filtered. This process is known is leaching.
b. When Al(OH)3 is added in small quantity and diluted with water to sodium aluminate solution, the whole aluminium in the solution gets precipitated as Al(OH)3. The Al(OH)3 precipitate is separated from the solution. Then it is washed and heated strongly to form pure Al2O3 or alumina.

Question 6.
Define:
a. Cast iron
b. Wrought iron
a. Cast iron is formed by heating pig iron, scrap iron and coke. Cast iron contains about 3% of carbon. Cast iron expands on solidification. So these are used to make molds. Though it is strong, it is brittle.
b. When cast iron is purified, it becomes wrought iron which is comparatively a pure form of iron. Wrought iron contains about 0.2% to 0.5% of carbon. Small amounts of phosphorus, silicon, etc. are also present.

Short Answer Type Questions (Score 3)

Question 7.
Match columns A, B and C suitably.

Question 8.
The concentration methods of certain ores are given below. Why these methods are used?
a. Bauxite – Leaching
b. Magnetite – Magnetic separation
c. Copper pyrites – Froth floatation
a. Bauxite gets dissolved in hot concentrate NaOH. But the impurities does not dis-solve in this.
b. Magnetite, the ore of iron has magnetic properties but the impurities does not have.
c. Copper pyrites have a lesser density and impurities have higher density. Also, only the ore particles float in pine oil.

Question 9.
Explain the relationship between reactivity series of metals and metallurgy.
Metals such as K,”Na, Ca, Mg and Al are placed above in the reactivity series. Strong reducing agent like electricity is used in the production of these metals by the electrolysis of their molten metallic compounds. Weak reducing agent such as carbon/carbon monoxide is used for the production of Zn, Fe, Ni, Sn and Pb. Copper is produced by the oxidation-reduction reactions of metal sulfide. Ag, Au, etc

Question 10.

Purification of copper is depicted here.
a Identify the anode, cathode and electrolyte.
b. Write the chemical equation during electrolysis.
c. What is seen below the positive electrode?
a. Anode : Impure copper
Cathode : Pure copper
electrolyte : aqeous solution of CuSO4 to which H2SO4 is added.

b. At anode : Cu → Cu2+ + 2e
At cathode : Cu2+ + 2e → Cu

c. Anode mud – impurities in impure copper

Question 11.
Certain alloys are given below.
i. Nichrome
ii. Stainless steel
a. What are the constituent elements in them?
b. What is the reason for the difference in their properties?
c. Write one use of each.
i. Nichrome: Fe, Ni, Cr, C
ii. Stainless steel: Fe, Cr, Ni, C
b. The constituent elements are same in both but their ratios are different. So their properties also differ.
c. Nichrome : for making heating coils Stainless steel: to make utensils

Long Answer Type Questions (Score 4)

Question 12.
Describe the following:
a. Calcination
b. Roasting v
Extraction of metals from the concentrated ore have 2 stages:-
a. Calcination: It is the process in which the ore is heated in the absence of air at a temperature below its melting point so that the moisture content of ore, volatile impurities, bio substances, etc. can be removed. Along with this, metal carbonates and hydroxides are converted into its oxide.

b. Roasting: It is the process in which the ore is heated in the presence of air at a temperature below its melting point so that the moisture content of ore, sulfur, phosphorous, etc, are converted into its oxide and can be removed. Sulfide ores also get converted into oxides.

Question 13.
Complete the table.

a. Haematite
b. Levigation
c. Roasting
d. Impurities with less density are removed.
e. Moisture content is removed. Sulfur, Arsenic, phosphorous, etc. are converted into its oxides. As they are in gaseous state, these are also removed.

Question 14.
Minerals of certain metals are given below. Write down the refining method of each.
a. Tin
b. Copper
c. Zinc
f. Silver
g. Mercury