1. The shape of $CH_4$ is

A. linear

B. planar

C. pyramidal

D. tetrahedral ✔

Explanation:
Methane has four bonding pairs around carbon and no lone pair, giving a tetrahedral shape.

2. The crystal layers in graphite are held together by

A. covalent bond

B. electrostatic forces

C. ionic bond

D. van der Waals forces ✔

Explanation:
Weak van der Waals forces hold the layers of graphite together.

3. Hydrogen bonds are formed between molecules containing hydrogen bonded to a

A. strongly electronegative atom ✔

B. non-polar species

C. diatomic element

D. complex ion

Explanation:
Hydrogen bonding occurs when hydrogen is bonded to highly electronegative atoms like O, N, or F.

4. The two elements $X$ and $_{19}Y$ are in the same group because they have the same

A. valence electrons ✔

B. ionization energy

C. number of shells

D. atomic size

Explanation:
Elements in the same group have the same number of valence electrons.

5. Which of the following processes is used in food preservation in industry?

A. Carbon dating

B. Irradiation with gamma rays ✔

C. Nuclear fission

D. Nuclear fusion

Explanation:
Gamma irradiation kills microorganisms and prolongs food shelf life.

6. Which arrangement is in decreasing order of atomic radius?

A. $Li > Be > C > B$

B. $Li > B > Be > C$

C. $Li > Be > B > C$ ✔

D. $C > B > Be > Li$

Explanation:
Atomic radius decreases across a period from left to right.

7. The electron configuration of ${}^{26}Fe^{3+}$ is

A. $[Ar]\,4s^2 3d^6$

B. $[Ar]\,4s^2 3d^3$

C. $[Ar]\,4s^1 3d^4$

D. $[Ar]\,4s^0 3d^5$ ✔

Explanation:
$Fe^{3+}$ loses two $4s$ electrons and one $3d$ electron.

8. Which transition metal is not attracted to an external magnetic field?

A. Cu

B. Fe

C. Ti

D. Zn ✔

Explanation:
Zinc has completely paired electrons and is diamagnetic.

9. An atom $W$ has 17 electrons and 18 neutrons. The correct representation is

A. $^{17}_{18}W$

B. $^{18}_{17}W$

C. $^{35}_{17}W$ ✔

D. $^{35}_{18}W$

Explanation:
Mass number = $17 + 18 = 35$; atomic number = 17.

10. The relative atomic mass of chlorine is not a whole number because

A. it is the weighted average mass of its isotopes ✔

B. it is the average mass of all elements

C. it has strong oxidizing ability

D. it has more neutrons than protons

Explanation:
Chlorine exists naturally as a mixture of isotopes.

11. $NH_4^+$ is formed from $NH_3$ and $H^+$ by

A. covalent bonding

B. dative bonding ✔

C. hydrogen bonding

D. ionic bonding

Explanation:
Nitrogen donates a lone pair to $H^+$, forming a dative bond.

12. How many lone pairs of electrons are present in HF?

A. 0

B. 1

C. 2

D. 3 ✔

Explanation:
Fluorine has three lone pairs in HF.

13. An aqueous solution of $Na_2CO_3$ is

A. acidic

B. alkaline ✔

C. amphoteric

D. neutral

Explanation:
Carbonate ions hydrolyze to produce $OH^-$ ions.

14. A mixture contains $0.256\,g$ of $H_2$ and $2.00\,g$ of $O_2$. The mole ratio of hydrogen to oxygen is

Explanation:
Moles of $H_2 = \frac{0.256}{2} = 0.128$
Moles of $O_2 = \frac{2.00}{32} = 0.0625$
Ratio $= 0.128 : 0.0625 = 2 : 1$

15. If $0.20\,mol\,dm^{-3}$ $NaOH$ yields $5.0\,g$, the volume used is

A. $600\,cm^3$

B. $625\,cm^3$ ✔

C. $1000\,cm^3$

D. $1600\,cm^3$

Explanation:
Molar mass of $NaOH = 40$
Moles $= \frac{5}{40} = 0.125$
Volume $= \frac{0.125}{0.20} = 0.625\,dm^3 = 625\,cm^3$

16. The oxidation number of sulphur in $SO_4^{2-}$ is

A. +2

B. +3

C. +4

D. +6 ✔

Explanation:
Sulphur has an oxidation state of +6 in sulphate.

17. The mass of $800\,cm^3$ of a gas at s.t.p. is $1.0\,g$. The molar mass is

A. $18.0\,g\,mol^{-1}$

B. $22.4\,g\,mol^{-1}$

C. $28.0\,g\,mol^{-1}$ ✔

D. $36.0\,g\,mol^{-1}$

Explanation:
$800\,cm^3 = 0.8\,dm^3$
Moles $= \frac{0.8}{22.4}$
Molar mass $= \frac{1.0 \times 22.4}{0.8} = 28$

18. A mixture of an insoluble solid U and water is best separated by

A. chromatography

B. sublimation

C. filtration ✔

D. separating funnel

Explanation:
Filtration separates an insoluble solid from a liquid.

19. The following set-up demonstrates hydrogen bromide vapour

A. diffusion ✔

B. dissolution

C. evaporation

D. sublimation

Explanation:
Gases spread by diffusion.

20. Which statement about equilibrium is correct?

A. reaction is irreversible

B. reaction goes to completion

C. equilibrium is re-established when stress is applied ✔

D. catalyst changes equilibrium position

Explanation:
According to Le Chatelier’s principle, equilibrium shifts to counter stress.

21. Boyle’s law is expressed as

A. $P \propto V$ at constant $T$

B. $V \propto T$ at constant $P$

C. $P \propto \frac{1}{V}$ at constant $T$ ✔

D. $V \propto \frac{1}{T}$ at constant $P$

Explanation:
Pressure is inversely proportional to volume at constant temperature.

22. Vapour pressure of a liquid increases when the

A. liquid is saturated with salt

B. volume increases

C. temperature falls

D. temperature rises ✔

Explanation:
Higher temperature increases kinetic energy of molecules.

23. Volatile liquids have

A. high vapour pressure and low boiling point ✔

B. high vapour pressure and high boiling point

C. low vapour pressure and low boiling point

D. low vapour pressure and high boiling point

Explanation:
Volatile liquids evaporate easily.

24. Mixing a strong acid with a strong base produces

A. electrical energy

B. heat ✔

C. light

D. sound

Explanation:
Neutralization reactions are exothermic.

25. Zinc oxide is amphoteric because it

A. forms acid salts

B. is an insoluble base

C. forms double salts

D. reacts with acids and bases ✔

Explanation:
Amphoteric substances react with both acids and bases.

26. Which substance is an alkali?

A. Lime (2.4)

B. Banana (4.6)

C. Distilled water (7.0)

D. Milk of magnesia (10.5) ✔

Explanation:
Alkalis have pH greater than 7.

27. Gases produced when $Cu(NO_3)_2$ is heated are

A. $NO$ and $NO_2$

B. $O_2$ and $NO_2$ ✔

C. $CO_2$ and $NO$

D. $NO_2$ and $N_2O_4$

Explanation:
Thermal decomposition gives $NO_2$ and $O_2$.

28. Which salt gives an alkaline solution on hydrolysis?

A. $NH_4Cl$

B. $AlCl_3$

C. $CH_3COONa$ ✔

D. $NH_4NO_3$

Explanation:
Salt of a weak acid and strong base gives alkaline solution.

29. Volume of $0.02\,mol\,dm^{-3}\,Na_2CO_3$ needed to neutralize $40\,cm^3$ of $0.10\,mol\,dm^{-3}\,HCl$ is

A. $200\,cm^3$ ✔

B. $100\,cm^3$

C. $40\,cm^3$

D. $20\,cm^3$

Explanation:
Using $C_1V_1 = C_2V_2$ and mole ratio $1:2$.

30. The rate of hydrogen evolution is fastest in the set-up with

Explanation:
Fastest rate occurs with highest acid concentration and powdered metal.

31. Which factor affects the equilibrium constant?

A. concentration

B. temperature ✔

C. pressure

D. volume

Explanation:
Only temperature changes the equilibrium constant.

32. From the energy profile diagram of an exothermic reaction, $\Delta H$ is

A. $120\,kJ\,mol^{-1}$

B. $80\,kJ\,mol^{-1}$

C. $60\,kJ\,mol^{-1}$ ✔

D. $40\,kJ\,mol^{-1}$

Explanation:
$\Delta H$ is the difference between reactants and products.

33. Which condition increases the yield of $NH_3$?

A. addition of catalyst

B. increase in temperature

C. increase in volume

D. increase in pressure ✔

Explanation:
High pressure favors ammonia formation.

34. The function of $MnO_2$ in the reaction is

A. catalyst

B. dehydrating agent

C. oxidizing agent ✔

D. reducing agent

Explanation:
$MnO_2$ oxidizes $HCl$ to chlorine gas.

35. The reaction at the anode during electrolysis of $CuSO_4(aq)$ using carbon electrodes is

A. $2H^+ + 2e^- \rightarrow H_2$

B. $Cu^{2+} + 2e^- \rightarrow Cu$

C. $4OH^- - 4e^- \rightarrow 2H_2O + O_2$ ✔

D. $SO_4^{2-} - 2e^- \rightarrow SO_2 + O_2$

Explanation:
Hydroxide ions are oxidized at the anode.

36. Reduction is the process of

A. gain of oxygen

B. loss of hydrogen

C. loss of oxygen ✔

D. addition of electronegative elements

Explanation:
Reduction involves loss of oxygen or gain of electrons.

37. Ethene molecules form a long chain compound called a

A. dimer

B. monomer

C. polymer ✔

D. trimer

Explanation:
Ethene undergoes addition polymerization.

38. The compound that determines octane rating of petrol is

A. 1,2,3-trimethylpentane

B. 2,3,5-trimethyloctane

C. 2,3,5-trimethylpentane

D. 2,2,4-trimethylpentane ✔

Explanation:
Iso-octane defines the octane scale.

39. The reaction $C_{12}H_{26} \rightarrow 5C_2H_4 + C_2H_6$ illustrates

A. addition

B. cracking ✔

C. hydrogenation

D. polymerization

Explanation:
Large hydrocarbons are broken into smaller ones.

40. The IUPAC name of $HOOC–COOH$ is

A. ethan-1,2-dioic acid ✔

B. ethanoic acid

C. oxalic acid

D. propan-1,2-dioic acid

Explanation:
$HOOC–COOH$ is ethanedioic (oxalic) acid.

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