chemistry MCQs - 12th class Chapter 05 Mcqs

1

Which elements are known as 'salt formers' from the Greek words 'hals' and 'gennan'?

A

Noble Gases

B

Alkali Metals

C

Halogens

D

Transition Metals

2

What is the physical state of bromine at room temperature and pressure?

A

Gas

B

Solid

C

Plasma

D

Liquid

3

Which halogen is radioactive and has a most stable isotope with a half-life of only 8.3 hrs?

A

Fluorine

B

Astatine

C

Iodine

D

Bromine

4

What is the characteristic outer shell electronic configuration of halogens?

A

ns² np⁴

B

ns² np⁶

C

ns² np³

D

ns² np⁵

5

The increasing order of van der Waal's forces among halogens is explained by the increase in:

A

Electronegativity

B

Atomic Size and Mass

C

Ionization Energy

D

Electron Affinity

6

Why are the fluorides of Ca, Mg, Ba, and Sr insoluble in water?

A

Low lattice energies

B

High covalent character

C

High lattice energies

D

Small size of metal ions

7

Which of the following is NOT a reason for the peculiar behavior of fluorine?

A

Small atomic size

B

High electronegativity

C

Restriction of valence shell to an octet

D

High dissociation energy of F₂

8

Which halogen is the only one that combines directly with noble gases like Kr, Xe, and Rn?

A

Chlorine

B

Fluorine

C

Bromine

D

Iodine

9

What is the correct decreasing order of oxidizing power for halogens?

A

I₂ > Br₂ > Cl₂ > F₂

B

F₂ > Cl₂ > Br₂ > I₂

C

Cl₂ > F₂ > Br₂ > I₂

D

Br₂ > I₂ > Cl₂ > F₂

10

Which of the following factors does NOT contribute to the high oxidizing power of a halogen?

A

Low energy of dissociation

B

High electron affinity

C

Low hydration energy of its ions

D

High hydration energy of its ions

11

Which halogen can oxidize all other halide ions to their molecular forms?

A

Chlorine

B

Bromine

C

Iodine

D

Fluorine

12

Which hydrogen halide is a liquid at room temperature?

A

HCl

B

HBr

C

HI

D

HF

13

The exceptionally high boiling point of HF is due to:

A

van der Waal's forces

B

Covalent bonding

C

Hydrogen bonding

D

Ionic bonding

14

What is the correct order of increasing acidic strength for hydrogen halides?

A

HF < HCl < HBr < HI

B

HI < HBr < HCl < HF

C

HCl < HF < HBr < HI

D

HBr < HI < HF < HCl

15

Which oxide of chlorine is used commercially for bleaching wood pulp and water treatment?

A

Cl₂O

B

Cl₂O₇

C

ClO₂

D

Cl₂O₆

16

Iodine pentoxide (I₂O₅) is used for the quantitative analysis of which gas?

A

Carbon dioxide (CO₂)

B

Sulphur dioxide (SO₂)

C

Carbon monoxide (CO)

D

Hydrogen sulfide (H₂S)

17

The reaction of chlorine with cold (15°C) NaOH is an example of what type of reaction?

A

Neutralization

B

Oxidation

C

Reduction

D

Disproportionation

18

In the reaction of chlorine with hot (70°C) NaOH, what are the final products besides water?

A

NaCl and NaClO

B

NaCl and NaClO₃

C

NaClO and NaClO₂

D

Only NaCl

19

According to nomenclature, an oxyacid with the halogen in a +5 oxidation state is called a:

A

Halous acid

B

Hypohalous acid

C

Perhalic acid

D

Halic acid

20

What is the trend of acidic strength in the oxyacids of chlorine?

A

HClO < HClO₂ < HClO₃ < HClO₄

B

HClO₄ < HClO₃ < HClO₂ < HClO

C

HClO₂ < HClO < HClO₄ < HClO₃

D

HClO₃ < HClO₄ < HClO < HClO₂

21

Perchloric acid (HClO₄) is prepared by distilling potassium perchlorate with which acid under reduced pressure?

A

Conc. HCl

B

Conc. HNO₃

C

Conc. H₂SO₄

D

Conc. H₃PO₄

22

What is the chemical formula for bleaching powder?

A

Ca(ClO)₂

B

CaCl₂

C

Ca(OCl)Cl

D

Ca(ClO₃)₂

23

The activity of bleaching powder is measured in terms of its:

A

Available oxygen

B

Available chlorine

C

Available calcium

D

Available hypochlorite

24

Freons, used as refrigerants and aerosol propellants, are low molecular mass compounds of:

A

Fluorochlorocarbons

B

Bromochlorocarbons

C

Iodochlorocarbons

D

Hydrocarbons

25

Teflon is a polymerized compound of:

A

Tetrafluoroethylene

B

Trichloroethylene

C

Polyvinyl chloride

D

Hexafluoroethane

26

Which compound is added to leaded gasoline to prevent lead oxide deposits?

A

Ethylene dichloride

B

Ethylene dibromide

C

Methyl bromide

D

Ethyl chloride

27

A diet with insufficient iodide leads to the enlargement of which gland?

A

Pituitary

B

Adrenal

C

Pancreas

D

Thyroid

28

What is the most abundant noble gas in the atmosphere?

A

Helium

B

Neon

C

Argon

D

Krypton

29

Which noble gas has the lowest boiling point of any known substance?

A

Helium

B

Neon

C

Argon

D

Radon

30

The weak forces of attraction between noble gas atoms are of what type?

A

Ionic bonds

B

Covalent bonds

C

Hydrogen bonds

D

van der Waals' forces

31

What is the oxidation state of Xenon in XeF₆?

A

+2

B

+4

C

+6

D

+8

32

Which compound is formed from the slow hydrolysis of XeF₆?

A

XeO₄

B

XeOF₄

C

XeO₃

D

XeOF₂

33

A mixture of 80% helium and 20% oxygen is used for breathing by:

A

Astronauts

B

Mountain climbers

C

Sea divers

D

Pilots

34

Which noble gas is used in bactericidal lamps?

A

Argon

B

Krypton

C

Xenon

D

Neon

35

Which noble gas, being radioactive, is used in radiotherapy for cancer?

A

Helium

B

Argon

C

Xenon

D

Radon

36

What color is liquid bromine?

A

Pale yellow

B

Greenish yellow

C

Red-brown

D

Greyish black

37

Which halogen exists as a shiny greyish black solid at room temperature?

A

Fluorine

B

Chlorine

C

Bromine

D

Iodine

38

Which of the following hydrogen halides has the highest bond energy?

A

HF

B

HCl

C

HBr

D

HI

39

The anhydride of perchloric acid (HClO₄) is:

A

Cl₂O

B

ClO₂

C

Cl₂O₅

D

Cl₂O₇

40

Silver bromide is widely used in which industry?

A

Pharmaceutical

B

Photography

C

Plastics

D

Textile

41

What is the shape of the OF₂ molecule?

A

Linear

B

Trigonal planar

C

Bent

D

Tetrahedral

42

When bleaching powder reacts with excess acid, what gas is released?

A

Oxygen

B

Hypochlorous acid

C

Chlorine

D

Hydrogen

43

Which halogen causes burns on the skin that heal slowly?

A

Fluorine

B

Chlorine

C

Bromine

D

Iodine

44

Halothane (CF₃CHBrCl) is used as a(n):

A

Refrigerant

B

Antiseptic

C

Anaesthetic

D

Fungicide

45

What is the commercial name for polymerized tetrafluoroethylene?

A

Freon

B

PVC

C

Halothane

D

Teflon

46

The reaction of chlorine with slaked lime produces:

A

Calcium chloride

B

Calcium hypochlorite

C

Bleaching powder

D

Calcium chlorate

47

In the Hasenclever's method, chlorine is introduced into which cylinder?

A

The uppermost

B

The middle

C

The lowest

D

All cylinders simultaneously

48

The solubility of noble gases in water increases with:

A

Decreasing atomic number

B

Increasing atomic number

C

Increasing temperature

D

Decreasing pressure

49

Xenon tetraoxide (XeO₄) is obtained by reacting sodium perxenate with:

A

Water

B

Hydrochloric acid

C

Concentrated Sulphuric acid

D

Sodium hydroxide