chemistry MCQs - 12th class Chapter 04 Mcqs

1

Which element in Group VA is a colourless gas at room temperature?

A

Phosphorus

B

Arsenic

C

Nitrogen

D

Bismuth

2

The principal oxidation states for all Group VA elements are:

A

+1, +2

B

+3, +5

C

+2, +4

D

+1, +3

3

Which of the following is considered a metalloid in Group VA?

A

Nitrogen

B

Phosphorus

C

Bismuth

D

Arsenic

4

The allotropes of phosphorus mentioned as more important are:

A

Red and Black

B

White and Black

C

Red and White

D

Yellow and Red

5

Nitrogen constitutes about what percentage of air by volume?

A

21%

B

78%

C

50%

D

90%

6

Dinitrogen oxide (N2O) is commonly known as:

A

Tear gas

B

Nitric oxide

C

Laughing gas

D

Nitrogen peroxide

7

Which compound is prepared by heating ammonium nitrate to about 200°C?

A

NO

B

N2O

C

NO2

D

N2O3

8

When nitrogen oxide (NO) reacts with oxygen, it forms a reddish-brown gas. What is this gas?

A

N2O

B

N2O4

C

NO2

D

N2O5

9

The 'Ring Test' is used to confirm the presence of which ions?

A

Sulphate

B

Chloride

C

Nitrate

D

Phosphate

10

What is the product when nitrogen dioxide (NO2) is cooled and frozen?

A

Yellow liquid NO2

B

Colourless solid N2O4

C

Reddish-brown gas NO

D

Blue acidic solution

11

Dissolving dinitrogen trioxide (N2O3) in water at 0°C prepares which acid?

A

Nitric acid

B

Hyponitrous acid

C

Pernitric acid

D

Nitrous acid

12

In the Birkeland and Eyde's process, what is the initial temperature of the electric arc used to combine N2 and O2?

A

1000°C

B

2000°C

C

3000°C

D

600°C

13

Concentrated nitric acid is a colourless volatile liquid with a specific gravity of:

A

1.00

B

1.53

C

2.05

D

0.98

14

Which of these metals does NOT react with nitric acid?

A

Magnesium

B

Copper

C

Gold

D

Zinc

15

Aqua regia is a mixture of concentrated HNO3 and concentrated HCl in what volume ratio?

A

1:3

B

3:1

C

1:1

D

2:1

16

The name 'Phosphorus' comes from a Greek word meaning:

A

Light bearing

B

Acid former

C

Water hating

D

Bone component

17

Bone ash is an important source of phosphorus and contains about 80% of what compound?

A

Calcium carbonate

B

Calcium sulphate

C

Calcium phosphate

D

Calcium chloride

18

White phosphorus exists as tetraatomic molecules with the formula:

A

P2

B

P

C

P8

D

P4

19

Phosphorus trichloride (PCl3) is prepared by passing dried chlorine over:

A

Red phosphorus

B

Melted white phosphorus

C

Phosphorus pentoxide

D

Bone ash

20

What is the boiling point of phosphorus trichloride (PCl3)?

A

100°C

B

76°C

C

-112°C

D

280°C

21

Phosphorus pentachloride (PCl5) sublimes at about:

A

100°C

B

200°C

C

360°C

D

50°C

22

Burning white phosphorus in a limited supply of air produces:

A

P2O5

B

P4O10

C

P2O3

D

POCl3

23

Phosphorus pentoxide (P2O5) is a powerful:

A

Oxidizing agent

B

Reducing agent

C

Hydrating agent

D

Dehydrating agent

24

Which acid is formed when phosphorus trioxide (P2O3) reacts with cold water?

A

Orthophosphoric acid

B

Metaphosphoric acid

C

Phosphorus acid

D

Pyrophosphoric acid

25

Orthophosphoric acid (H3PO4) is a:

A

Weak monobasic acid

B

Strong tribasic acid

C

Weak tribasic acid

D

Strong dibasic acid

26

The elements of Group VIA are also called 'chalcogens', which is Greek for:

A

Oxygen former

B

Sulphur family

C

Copper giver

D

Ore producer

27

Which element in Group VIA is the most electronegative?

A

Sulphur

B

Oxygen

C

Selenium

D

Tellurium

28

Oxygen comprises about what percentage of the Earth's crust?

A

25%

B

89%

C

50%

D

48%

29

Which property is shown by all elements of Group VIA?

A

Catenation

B

High conductivity

C

Metallic nature

D

Allotropy

30

Which of the following is a key difference between oxygen and sulphur?

A

Oxygen is a gas, sulphur is a solid at ordinary temp.

B

Both are soluble in water

C

Oxygen is combustible, sulphur helps combustion

D

Both show -2 oxidation state only

31

Sulphuric acid was first prepared by the Muslim scientist:

A

Al-Razi

B

Ibn Sina

C

Jabir bin Hayyan

D

Al-Kindi

32

The modern Contact Process for manufacturing H2SO4 uses what catalyst?

A

Fe2O3

B

V2O5

C

Pt

D

Ni

33

In the Contact Process, what is the optimal temperature range for the oxidation of SO2 to SO3?

A

100-200°C

B

200-300°C

C

400-500°C

D

600-700°C

34

The substance 'Oleum' formed in the Contact Process has the formula:

A

H2SO4

B

H2SO3

C

H2S2O7

D

SO3

35

Pure sulphuric acid has a boiling point of:

A

10.5°C

B

120°C

C

338°C

D

100°C

36

The reaction of H2SO4 with sugar (C12H22O11) demonstrates its property as a(n):

A

Oxidizing agent

B

Acid

C

Reducing agent

D

Dehydrating agent

37

When hot concentrated sulphuric acid reacts with copper, it produces CuSO4, water, and:

A

H2

B

SO3

C

SO2

D

S

38

Which of the following is NOT a use of sulphuric acid?

A

Manufacture of fertilizers

B

Food preservation

C

Refining of petroleum

D

In electrical batteries

39

The metallic character in Group VA __________ as you go down the group.

A

Decreases

B

Increases

C

Remains the same

D

First increases, then decreases

40

What is the physical appearance of Antimony (Sb) as listed in the table?

A

Colourless gas

B

Black solid

C

Metallic solid

D

Liquid

41

The reaction of NO with FeSO4 is the basis for the:

A

Haber Process

B

Contact Process

C

Ring Test

D

Birkeland and Eyde's process

42

Nitrous acid (HNO2) acts as an oxidizing agent when it reacts with:

A

KMnO4

B

HI

C

Bromine water

D

H2SO3

43

Aqua regia can dissolve noble metals like gold by producing:

A

Nascent hydrogen

B

Nitric oxide

C

Nascent chlorine

D

Nitrous oxide

44

Which allotrope of phosphorus is the most stable under ordinary conditions?

A

White phosphorus

B

Red phosphorus

C

Black phosphorus

D

Yellow phosphorus

45

Phosphorus pentoxide reacts with hot water to form:

A

Metaphosphoric acid

B

Orthophosphoric acid

C

Phosphorus acid

D

Pyrophosphoric acid

46

Which Group VIA element has the highest boiling point?

A

Oxygen

B

Sulphur

C

Selenium

D

Tellurium

47

Sulphur reacts with alkali solutions to form sulphides and:

A

Sulphates

B

Sulphites

C

Thiosulphates

D

Bisulphates

48

In the Contact Process, the 'Arsenic Purifier' contains shelves packed with:

A

Activated charcoal

B

Silica gel

C

Ferric hydroxide

D

Calcium oxide

49

Decomposition of oxalic acid by concentrated H2SO4 produces CO2, water, and:

A

CO

B

O2

C

H2

D

SO2