Class 10 Chemistry Chapter 6 Important Questions with Answers Kerala Syllabus

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SSLC Chemistry Chapter 6 Important Questions Kerala Syllabus

Metals Class 10 Important Questions

Question 1.
Find the relation and fill in the blanks.
Copper pyrites : CuFeS₂
Zinc blende : …………………………
a) ZnS (Chemical formula)
b) Zinc (Ore)
c) Magnetite (Iron)
d) Leaching (Concentration method)
Answer:
a) ZnS (Chemical formula)

Question 2.
Bauxite is the ore of ………………………… metal
a) Iron
b) Aluminium
c) Zinc
d) Copper
Answer:
b) Aluminium

Question 3.
Find the relation and fill in the blanks
Bauxite : Leaching
Tinstone : ……………………….
Answer:
Magnetic separation (Method of concentration)

Question 4.
The ore of a metal is lighter than the impurities
Which method is suitable for its concentration?
a) Levigation
b) Magnetic separation
c) Froth floatation
d) Leaching
Answer:
c) Froth floatation

Question 5.
Which is the method used to concentrate Sulphide ores?
a) Magnetic separation
b) Leaching
c) Froth floatation
d) Levigation
Answer:
c) Froth floatation

Question 6.
The metal which is refined by distillation is _____________ .
(Sn, Cu, Hg, Pb)
Answer:
Hg

Question 7.
Statement 1: Roasting refers to heating the concentrated ore at a temperature below the melting point in the presence of air.
Statement 2: Calcination refers to heating the concentrated ore in limited quantities or absence of air at a temperature below the melting point. Which of the following options is true, regarding these statements?
A. Statements 1 and 2 are correct.
B. Statement 1 is correct, but 2 is not correct.
C. Statement 1 is not correct, but 2 is correct.
D. Statements 1 and 2 are not correct.
Answer:
A. Statements 1 and 2 are correct

Question 8.
Match the following

Nature of Ore	Concentration method
(a) Ores are less dense than the impurities	(i) Levigation
(b) A solvent which dissolves the ore is used	(ii) Froth Floatation
(c) Ores are denser than the impurities	(iii) Leaching

Choose the correct answer from the options given below.

Answer:
D. (a) – (ii), (b) – (iii), (c) – (i)

Question 9.
Molten iron obtained from the blast fiimace contains 4% carbon and other impurities. What is this known as?
(Pig iron, Cast Iron, Wrought Iron)
Answer:
Pig iron

Question 10.
What are ores? Give any one example.
Answer:
A mineral from which a metal is economically, easily and quickly extracted is called the ore of the metal – for example, aluminium – bauxite

Question 11.
Find out the odd one. Give reason.
Haematite, Bauxite, magnetite, Iron pyrites
Answer:
Bauxite – Ore of Aluminium. Others are minerals of Iron.

Question 12.
Choose the suitable method used in each of the following processes from the bracket.
[Liquation, Leaching, Froth floatation, Distillation]
a) Concentration of sulphide ores.
b) Refining of metals with low boiling points.
Answer:
a) Froth floatation
b) Distillation

Question 13.
a) Name a method of concentration of an ore in which impurities are heavier than the ore particles.
b) Select an ore which can be concentrated by using this method.
(Fe₃O₄, ZnCO₃, CaCO₃, ZnS)
Answer:
a) Froth floatation
b) ZnS

Question 14.
Concentrated Cu₂S is converted into oxide by roasting.
a) Write the process of roasting.
b) How impurities like sulphur and phosphorus are removed in this process?
Answer:
a) Roasting refers to heating the concentrated ore at a temperature below its melting point in the presence of air.
b) Sulphur and phosphorous are removed as their oxides.

Question 15.
Calcination and Roasting are two methods of conversion of concentrated ore into its oxide.
a) How does Roasting differ from Calcination?
b) Cu2S ore is converted into Cu₂O by ……………………..
process
Answer:
a) Roasting refers to heating the concentrated ore at a temperature below its melting point in the presence of air

b) Roasting

Question 16.
What is cathodic protection? Explain its underlying principle using an example involving two metals.
Answer:
Cathodic protection is a method used to prevent the corrosion of a metal by making it the cathode in an electrochemical cell. This process is a key form of galvanic corrosion prevention.

The principle is to connect the metal you want to protect (the cathode) to a more reactive metal (the anode), known as a sacrificial anode. The sacrificial anode will corrode preferentially, releasing electrons and protecting the cathode from rusting.

For example, when an iron pipe is buried underground, a block of a more reactive metal like ^ns magnesium is connected to it. The magnesium corrodes over time, acting as the anode and sacrificially protecting the iron pipe, which becomes the cathode.

Question 17.
Complete the table.

Metal	Method of refining	Reason for selecting the method
Lead	(a)	Low melting point
Cadmium	Distillation	(b)

Answer:
a) Liquation
b) Low boiling point

Question 18.
Haematite is converted into iron by using the blast furnace.
a) Which are the substances fed into the blast furnace along with the ore of iron?
b) Which compound acts as the reducing agent in the blast furnace?
Answer:
a) Limestone, Coke
b) Carbon monoxide (CO)

Question 19.
Complete the table.

Characteristics of Ore	Method of Concentration
i. Ore particles are lighter than the impurities	……………..(a)……………
ii. Ore particles are heavier than the impurities	……………..(b)……………
iii. Ore and impurities do not dissolve in the same solvent	……………..(c)……………

Answer:
a) Froth floatation
b) Levigation or Hydraulic washing
c) Leaching

Question 20.
Some metals and their refining methods are given. Find the appropriate pair.

Answer:

Question 21.
Match columns A, B and C suitably.

A Characteristics of ore	B Method of concentration	C Example
Ore particles are heavier than the impurities	Froth floatation	Tinstone
Ore particles are lighter than the impurities	Magnetic separation	Ore of gold
Magnetic nature of the ore	Levigation	Zinc Sulphide

Answer:

A Characteristics of ore	B Method of concentration	C Example
Ore particles are heavier than the impurities	Levigation	Ore of gold
Ore particles are lighter than the impurities	Froth floatation	Zinc Sulphide
Magnetic nature of the ore	Magnetic separation	Tinstone

Question 22.
Chemical equations of the reactions taking place in blast furnace during the industrial production of iron are given below.
i) C + O₂ → CO₂ + Heat
ii) CO₂ + C + Heat → 2CO
iii) Fe₂O₃ + 3CO → 2Fe + 3CO₂
iv) CaCO₃ → CaO + CO₂
v) CaO + SiO₂ → CaSiO₃
Answer the following questions.
a) Which compound acts as the reducing agent?
b) What is the function of CaO in the production of iron?
c) Which is the slag formed here?
Answer:
a) Carbon monoxide (CO)
b) Act as flux to remove Silica (SiO₂)
c) Calcium silicate (CaSiO₃)

Question 23.
Bauxite is the main ore of Aluminium.
a) Which method is used to concentrate bauxite?
b) Electricity is used as the reducing agent in the manufacture of Aluminium. Why?
c) Aluminium is obtained at which electrode during the electrolysis?
Answer:
a) Leaching
b) Aluminium is a highly reactive metal; thus strong reducing agent like electricity is used.
c) Cathode (Negative electrode)

Question 24.
Haematite is converted into iron by reactions taking place in the blast furnace.
a) Write the molecular formula of Haematite.
b) Which substance acts as the reducing agent in this process?
c) Molten iron is produced along with slag from the furnace. What is meant by slag?
d) Write the chemical equation that shows the formation of slag.
Answer:
a) Fe₂O₃
b) Carbon monoxide (CO)
c) Mixture of flux and gangue
d) CaO + SiO₃ → CaSiO₃

Question 25.
Zinc is an industrially important metal
a) Which is the ore of Zinc?
b) Write the name of the concentration method used for Zinc ore?
c) What is the process used in the conversion of zinc ore to zinc oxide after the concentration of the ore?
d) Write the name of the purification method used for Zinc.
Answer:
a) Zinc blende (ZnS)
b) Froth floatation
c) Roasting
d) Distillation

Question 26.
Aluminium is very useful in our daily life.
a) Which is the ore of aluminium?
a) Which is the solution used to concentrate aluminium ore?
b) Why is cryolite added to alumina during its electrolysis?
c) Write the equation of reduction of aluminium ion.
Answer:
a) Bauxite
b) Hot Concentrated NaOH solution.
c) Cryolite is added to alumina to reduce its melting point and increase its electrical conductivity.
d) Al³⁺ + 3e^– → Al