chemistry MCQs - 10th class Chapter 08 Mcqs

1

The process of extracting a metal in a pure state from its ore is called?

A

Roasting

B

Smelting

C

Metallurgy

D

Concentration

2

Which of the following is an ore of copper?

A

Bauxite

B

Limestone

C

Chalcopyrite

D

Haematite

3

The earthly and other impurities associated with minerals are known as?

A

Concentrate

B

Gangue

C

Slag

D

Matte

4

The process of removing gangue from the ore is known as?

A

Refining

B

Smelting

C

Bessemerization

D

Concentration

5

Gravity separation is based on the differences in what property?

A

Wetting characteristics

B

Magnetic properties

C

Densities

D

Boiling points

6

Froth flotation process is used for the concentration of which type of ores?

A

Oxide ores

B

Carbonate ores

C

Sulphide ores

D

Halide ores

7

In the froth flotation process, ore particles are preferentially wetted by?

A

Water

B

Acid

C

Pine oil

D

Alkali

8

Electromagnetic separation is suitable for separating which kind of substances?

A

Substances with different densities

B

Magnetic substances from non-magnetic ones

C

Substances soluble in oil

D

Substances soluble in water

9

The process of heating a concentrated ore to a high temperature in excess of air is called?

A

Smelting

B

Roasting

C

Calcination

D

Refining

10

In the smelting of copper ore, what is added as a flux to remove impurities?

A

Limestone

B

Coke

C

Sand

D

Pine oil

11

The molten mixture of cuprous sulphide and ferrous sulphide (Cu2S.FeS) is called?

A

Slag

B

Gangue

C

Matte

D

Blister copper

12

Iron silicate (FeSiO3) formed during smelting is also known as?

A

Matte

B

Slag

C

Concentrate

D

Flux

13

Bessemerization is carried out in a pear-shaped converter that is fixed on a?

A

Fixed stand

B

Conveyor belt

C

Pivot

D

Roller

14

Copper obtained after the Bessemerization process is called blister copper because?

A

It is 99.9% pure

B

It has a blister-like shape

C

Dissolved gases escape forming blisters

D

It is cooled rapidly

15

Blister copper is approximately how much pure?

A

90%

B

95%

C

98%

D

99.9%

16

In the electrolytic refining of copper, the anode is made of?

A

Pure copper

B

Graphite

C

Impure copper

D

Steel

17

During the electrolytic refining of copper, impurities like gold and silver settle down as?

A

Anode mud

B

Cathode mud

C

Slag

D

Gangue

18

Which of the following is NOT a raw material for the Solvay process?

A

Sodium chloride (NaCl)

B

Limestone (CaCO3)

C

Ammonia (NH3)

D

Sulphuric acid (H2SO4)

19

The principle of the Solvay process lies in the low solubility of what compound at 15°C?

A

NaCl

B

NH4Cl

C

NaHCO3

D

CaCO3

20

In the Solvay process, the ammonical brine is carbonated in the?

A

Ammoniating tower

B

Lime kiln

C

Carbonating tower

D

Recovery tower

21

In the Solvay process, how is sodium carbonate (Na2CO3) obtained?

A

By filtering the brine

B

By heating sodium bicarbonate (NaHCO3)

C

By reacting NaCl with CaCO3

D

By cooling the ammonical brine

22

Which valuable substance is recovered in the ammonia recovery tower in the Solvay process?

A

CO2

B

NH3

C

NaCl

D

CaCO3

23

The only waste product in the Solvay's process is?

A

NH4Cl

B

CaO

C

CaCl2

D

CO2

24

Urea is a nitrogenous fertilizer that contains what percentage of nitrogen?

A

46.6%

B

90%

C

78%

D

50%

25

Which two substances are the raw materials for the manufacture of urea?

A

Ammonia and Carbon dioxide

B

Nitrogen and Hydrogen

C

Ammonia and Oxygen

D

Methane and Steam

26

In urea manufacturing, ammonia and carbon dioxide first react to form?

A

Urea

B

Ammonium carbamate

C

Ammonium nitrate

D

Ammonium chloride

27

The conversion of ammonium carbamate to urea is a ________ process.

A

Hydration

B

Oxidation

C

Reduction

D

Dehydration

28

What is the major use of urea, accounting for about 90% of its consumption?

A

As a raw material for chemicals

B

As an animal feed additive

C

As a fertilizer

D

In manufacturing explosives

29

Petroleum is a complex mixture of several gaseous, liquid, and solid?

A

Alcohols

B

Esters

C

Hydrocarbons

D

Acids

30

Petroleum was formed from the decomposition of?

A

Rocks and minerals

B

Volcanic ash

C

Dead plants and animals

D

Meteorites

31

The refining of crude oil is carried out by a process called?

A

Fractional distillation

B

Steam distillation

C

Simple distillation

D

Destructive distillation

32

In fractional distillation, substances are separated based on their?

A

Density

B

Solubility

C

Melting point

D

Boiling point

33

What is the boiling range of the Gasoline (Petrol) fraction?

A

up to 25°C

B

30 to 80°C

C

80 to 170°C

D

170 to 250°C

34

Which petroleum fraction is used as a fuel in jet engines?

A

Gasoline

B

Diesel oil

C

Kerosene oil

D

Petroleum gas

35

The fraction of petroleum used as a fuel for buses, trucks, and railway engines is?

A

Fuel oil

B

Diesel oil

C

Kerosene oil

D

Petrol

36

Which of these is obtained from the fractional distillation of residual oil?

A

Gasoline

B

Kerosene oil

C

Diesel oil

D

Asphalt

37

The process for preparing ammonia for urea synthesis is called?

A

Solvay's process

B

Haber's process

C

Bessemerization

D

Fractional distillation

38

What is the chemical formula of urea?

A

NH2COONH4

B

NH2CONH2

C

NaHCO3

D

Na2CO3

39

Which petroleum fraction is used for dry cleaning purposes?

A

Kerosene oil

B

Gasoline

C

Petroleum ether

D

Diesel oil

40

What happens to the impure copper anode during electrorefining?

A

It gets thicker

B

It remains unchanged

C

It dissolves

D

It turns into pure copper

41

In the Solvay process, the lime kiln is used to produce CO2 from?

A

NaCl

B

NH3

C

CaCO3

D

CaO

42

What is the composition of matte?

A

Cu2O + FeO

B

Cu2S + FeS

C

Cu + Fe

D

FeSiO3

43

Which method is based on the wetting characteristics of ore and gangue particles with oil and water?

A

Gravity separation

B

Froth flotation

C

Electromagnetic separation

D

Roasting

44

The solid natural materials found beneath the Earth's surface are called?

A

Ores

B

Gangue

C

Minerals

D

Slag

45

Which company is the biggest fertilizer manufacturer in Pakistan with 59% market share?

A

Engro Chemicals

B

Dawood Hercules

C

Sindh Alkalies Limited

D

Fauji Fertilizer Company

46

Crude oil is heated to what temperature in a furnace before being passed into the fractionating column?

A

100°C

B

250°C

C

400°C

D

600°C

47

How many fractions are obtained from the initial fractional distillation of crude oil up to 400°C?

A

4

B

6

C

8

D

10

48

The chemical formula for baking soda is?

A

Na2CO3

B

CaCO3

C

NaHCO3

D

NH4Cl

49

What is the purpose of adding coke during the smelting process?

A

To act as a flux

B

To act as a fuel

C

To form slag

D

To cool the furnace

50

Which of the following is a use for fuel oil?

A

Domestic fuel

B

Fuel in motor cars

C

To heat boilers and furnaces in ships and industries

D

Laboratory solvent