MCQ of Chemistry

1. The atmospheric pollution is generally measured in the units of

(a) mass percentage

(b) volume percentage

(c) volume fraction

(d) ppm

Ans. (d) ppm

2. Temperature dependent term among the following is –

(a) Molality

(b) Molarity

(c) Mole fraction

(d) Weight percentage

Ans. (b) Molarity

3. The law which indicates the relationship between solubility of a gas in liquid and pressure is

(a) Raoult’s law

(b) Henry’s law

(c) Lowering of vapour pressure

(d) Van’t Hoff law

Ans. (b) Henry’s law

4. Partial pressure of a solution component is directly proportional to its mole fraction. This is known as

(a) Henry’s law

(b) Raoult’s law

(c) Distribution law

(d) Ostwald’s dilution law

Ans. (b) Raoult’s law

5. Which of the following solutions shows positive deviation from Raoult’s law?

(a) Acetone + Aniline

(b) Acetone + Ethanol

(c) Water + Nitric acid

(d) Chloroform + Benzene

Ans. (b) Acetone + Ethanol

6. The system that forms maximum boiling azeotrope is

(a) Acetone-chloroform

(b) ethanol-acetone

(c) n-hexane-n-heptane

(d) carbon disulphide-acetone

Ans. (a) Acetone-chloroform

7. A plant cell shrinks when it is kept in a

(a) hypotonic solution

(b) hypertonic solution

(c) isotonic solution

(d) pure water

Ans. (b) hypertonic solution

8 .The osmotic pressure of a solution can be increased by

(a) increasing the volume

(b) increasing the number of solute molecules

(c) decreasing the temperature

(d) removing semipermeable membrane

Ans. (b) increasing the number of solute molecules

9. Sprinkling of salt helps in clearing the snow-covered roads in hills. The phenomenon involved in the process is

(a) lowering in vapour pressure of snow

(b) depression in freezing point of snow

(c) melting of ice due to increase in temperature by putting salt

(d) increase in freezing point of snow

Ans. (b) depression in freezing point of snow

10. The Van’t Hoff factor [i] for a dilute aqueous solution of the strong electrolyte barium hydroxide is?

(a) 0

(b) 1

(c) 2

(d) 3

Ans. (d) 3

11. The charge required for the reduction of 1 mol of MnO₄^– to MnO₂ is

(a) 1 F

(b) 3 F

(c) 5 F

(d) 6 F

Ans. (b) 3F

12. If limiting molar conductivity of Ca²⁺ and Cl^– are 119.0 and 76.3 S cm² mol^-1, then the value of limiting molar conductivity of CaCl₂ will be

(a) 195.3 S cm² mol^-1

(b) 271.6 S cm² mol^-1

(c) 43.3 S cm² mol^-1

(d) 314.3 S cm² mol^-1‘.

Ans. (b) 271.6 S cm² mol^-1

13. The emf of the cell:

Ni/ Ni²⁺ (1.0 M) ∣∣ Au³⁺ (1.0 M) / Au (E⁰= – 0.25 V for Ni²⁺/Ni; E⁰ = 1.5 V for Au⁺³/Au) is

(a) 1.25 V

(b) -1.25 V

(c) 1.75 V

(d) 2.0 V

Ans. (c) 1.75 V

14. In a dry cell, which of the following is the electrolyte?

(a) Potassium hydroxide

(b) Sulphuric acid

(c) Ammonium chloride

(d) Manganese dioxide

Ans. (c) Ammonium chloride

15. Which of the following statements about a lead storage cell (or a lead-acid battery) is false?

(a) It is a primary cell

(b) The cathode is made up of lead (IV) oxide

(c) The anode is made up of lead

(d) The electrolyte used is an aqueous solution of Sulphuric acid

Ans. (a) It is a primary cell

16. Which of the following observations is incorrect about the order of a reaction?

(a) Order of a reaction is always a whole number

(b) The stoichiometric coefficient of the reactants doesn’t affect the order

(c) Order of reaction is the sum of power to express the rate of reaction to the concentration terms of the reactants.

(d) Order can only be assessed experimentally

Ans. (a)

17. In the reaction 2A + B → A₂B, if the concentration of A is doubled and that of B is halved, then the rate of the reaction will

(a) decrease 2 times

(b) increase 4 times

(c) increase 2 times

(d) remain the same

Ans. (c)

18. when the rate of the reaction is equal to the rate constant, the order of the reaction is

(a) zero order

(b) first order

(c) second order

(d) third order

Ans. (a)

19. A substance ‘A’ decomposes by a first-order reaction starting initially with [A] = 2.00M and after 200min, [A] becomes 0.15M. For this reaction t_½ is

(a) 53.72 min

(b) 50.49 min

(c) 48.45 min

(d) 46.45 min

Ans. (a)

20. A catalyst alters, which of the following in a chemical reaction?

(a) Entropy

(b) Enthalpy

(c) Internal energy

(d) Activation energy

Ans. (d)

21. The number of unpaired electrons in gaseous species of Mn³⁺, Cr³⁺ and V³⁺ respectively are:

(a) 4, 4 and 2

(b) 3, 3 and 2

(c) 4,3 and 2

(d) 3.3 and 3

Ans. (c)

22. Gun metal is an alloy of:

(a) Cu and Al

(b) Cu and Sn

(c) Cu, Zn and Sn

(d) Cu, Zn and Ni

Ans. (c)

23. Which one of the following elements shows the maximum number of different oxidation states in its compounds?

(a) Eu

(b) La

(c) Cd

(d) Am

Ans. (d)

24. When potassium ferrocyanide crystals are heated with concentrated sulphuric acid, the gas evolved is

(a) Sulphur dioxide

(b) ammonia

(c) carbon monoxide

(d) carbon dioxide

Ans. (c)

25. Zinc and mercury do not show variable valency like d-block elements because

(a) they are soft

(b) their d-shells are complete

(c) they have only two electrons in the outermost subshell.

(d) their d-shells are incomplete

Ans. (b)

26. Which of the following products are obtained when Na₂CO₃ is added to a solution of copper sulphate?

(a) Basic copper carbonate, sodium sulphate and CO₂

(b) Copper hydroxide, sodium sulphate and CO₂

(c) Copper carbonate, sodium sulphate and CO₂

(d) Copper carbonate and sodium sulphate

Ans. (d)

27. The pair that has similar atomic radii is

(a) Mn and Re

(b) Ti and Hf

(c) Sc and Ni

(d) Mo and W

Ans. (d)

28. Silver nitrate produces a black stain on the skin due to

(a) being a strong reducing agent

(b) its corrosive action

(c) formation of complex compound

(d) its reduction to metallic silver

Ans. (d)

29. Lanthanoid contraction is due to increase in

(a) atomic number

(b) effective nuclear charge

(c) atomic radius

(d) valence electrons

Ans. (b) effective nuclear charge

30. In Fe (CO)₅, the Fe-C bond possesses:

(a) ionic character

(b) sigma character only

(c) pi character

(d) both sigma and pi characters

Ans. (d)

31. Which of the following statements about coordination compounds’ bonding is incorrect?

(a) Crystal Field Theory

(b) VSEPR Theory

(c) Valence Bond Theory

(d) Molecular Orbital Theory

Ans. (b)

32. Determine the proper name for K₂[PdCl₄].

(a) Potassium tetrachlorinepalladium(II)

(b) Potassium tetrachloridopalladate(I)Potassium

(c) Potassium tetrachloridopalladium(lI)

(d) tetrachlorinepalladate(II)

Ans. (b)

33. Which substance is used to determine the hardness of water using a simple titration?

(a) Mg(EDTA)

(b) Fe(EDTA)

(c) Na(EDTA)

(d) Co(EDTA)

Ans. (c)

34. The core atom of which of the following biologically significant coordination molecules is magnesium?

(a) Vitamin B12

(b) Haemoglobin

(c) Chlorophyll

(d) Carboxypeptidase-A

Ans. (c)

35. According to IUPAC nomenclature sodium nitroprusside dihydrate is named as

(a) Sodium pentacyanonitrosylferrate (II)

(b) Sodium nitroferrocyanide

(c) Sodium nitroferricyanide

(d) Sodium pentacyanonitrosylferrate (I)

Ans. (a)

36. What is the common name of 3-Bromopropene?

(a) Allyl bromide

(b) Vinyl bromide

(c) Tert-Butyl bromide

(a) Propylidene bromide

Ans. (a)

37. IUPAC name of CH₃CH₂C(Br) = CH – Cl is

(a) 2-bromo-1-chloro butene

(b) 1-chloro-2-bromo butene

(c) 3-chloro-2-bromo butene

(d) None of the above

Ans. (a)

38. Which of the following will have the maximum dipole moment?

(a) CH₃F

(b) CH₃CI

(c) CH₃Br

(d) CH₃I

Ans. (b)

39. Phosgene is a common name for

(a) phosphoryl chloride

(b) thionyl chloride

(c) carbon dioxide and phosphine

(d) carbonyl chloride

Ans. (d)

40. In the preparation of chlorobenzene from aniline, the most suitable reagent is

(a) Chlorine in the presence of ultraviolet light

(b) Chlorine in the presence of AlCl₃

(c) Nitrous acid followed by heating with CuCl₂

(d) HCl and Cu₂Cl₂

Ans. (c)

41. The decreasing order of boiling points of alkyl halides is

(a) RF> RCl> RBr> RI

(b) RBr > RCl> RI > RF

(c) RI> RBr> RCl> RF

(d) RCI > RF>RI> RBr

Ans. (c)

42. Chlorobenzene is prepared commercially by

(a) Raschig process

(b) Wurtz Fittig reaction

(c) Friedel-Craft’s reaction

(d) Grignard reaction

Ans. (a)

43. Finkelstein reaction for the preparation of alkyl iodide is based upon the fact that

(a) Sodium iodide is soluble in methanol, while sodium chloride is insoluble in methanol

(b) Sodium iodide is soluble in methanol, while NaCl and NaBr are insoluble in methanol

(c) Sodium iodide is insoluble in methanol, while NaCl and NaBr are soluble

(d) The three halogens differ considerably in their electronegativity

Ans. (b)

44. Which of the following statements about SN² mechanisms is incorrect?

(a) The transition state is stable

(b) The complete mechanism takes place in a single step

(c) The rate of the reaction depends on the concentration of both reactants

(d) There is an inversion of configuration

Ans. (a)

45. Which of the following catalyst in the chloroalkane reaction of a primary alcohol with HCI?

(a) red phosphorous

(b) concentrated H₂SO₄

(c) anhydrous ZnCl₂

(d) pyridine

Ans. (c)

46. C₂H₅OH + PCl₅ → C₂H₅Cl + HCI + ………

(a) Phosphorus acid

(b) Phosphoryl chloride

(c) Phosphorus trichloride

(d) Phosphoric acid

Ans. (b)

47. Which of the following substances has the highest melting point?

(a) Chloromethane (CH₃CI)

(b) Tetrachloromethane (CCl₄)

(c) Trichloromethane (CHCI₃)

(d) Dichloromethane (CH₂Cl₂)

Ans. (b)

48. Which sequence should isomeric dichlorobenzenes be boiled in?

(a) p-dichlorobenzene > 0-dichlorobenzene > m-dichlorobenzene

(b) m-dichlorobenzene >০-dichlorobenzene >p-dichlorobenzZene

(c) o-dichlorobenzene > m-dichlorobenzene > p-dichlorobenzene

(d) p-dichlorobenzene >m-dichlorobenzene > ০-dichlorobenzene

Ans. (a)

49. Which of the following statements about the interaction between C₂H₄ and Cl₂ in CCl₄ is incorrect?

(a) It results in the formation of a vicinal dihalide

(b) It results in the discharge of a reddish-brown colour

(c) It results in the formation of a colourless compound

(d) It results in the breaking of the C-C double bond

Ans. (b)

50. Benzene diazonium chloride on reaction with phenol in weakly basic medium gives

(a) diphenyl ether

(b) p-hydroxy azobenzene

(c) chlorobenzene

(d) Benzene

Ans. (b)

51. Phenol reacts with bromine in CS₂ at low temperature to give

(a) m-bromophenol

(b) ০-and p-bromophenol

(c) p-bromophenol

(d) 2,4,6-tribromophenol

Ans. (b)

52. Dehydration of alcohol is an example of

(a) addition reaction

(b) elimination reaction

(c) substitution reaction

(d) redox reaction

Ans. (b)

53. Which of the following is formed when phenol is exposed to air?

(a) ০-Bemzoquinone

(b) p-Benzoquinone

(c) Phenoquinone

(d) o-and p-Benzoquinone

Ans. (d)

54. The alcohol which does not react with Lucas’s reagent is

(a) isobutyl alcohol

(b) n-butanol

(c) tert-butyl alcohol

(d) sec-butyl alcohol

Ans. (b)

55. Which of these has the least unpleasant Odour?

(a) Methanal

(b) Butanal

(c) Propanal

(d) Ethanal

Ans. (b)

56. Reactions occur between aldehydes and ketones.

(a) nucleophilic addition

(b) electrophilic substitution

(c) electrophilic addition

(d) nucleophilic substitution

Ans. (a)

57. Which of the following is not a formaldehyde application?

(a) Preservation of biological specimens

(b) Preparation of acetic acid

(c) Silvering of mirrors

(d) Manufacturing of Bakelite

Ans. (b)

58. Which of the following compounds is formed when benzyl alcohol is oxidized with KMnO₄?

(a) CO₂ and H₂O

(b) Benzoic acid

(c) Benzaldehyde

(d) Benzophenone

Ans. (b)

59. The Rosenmund reaction can produce which of the following carbonyl compounds?

(a) Methanal

(b) Benzaldehyde

(c) Butanone

(d) Acetone

Ans. (b)

60. What is the most basic aromatic amine’s common name?

(a) Benzenamine

(b) Benzylamine

(c) Aniline

(d) Aminobenzene

Ans. (c)

61. When acetamide is converted to methylamine, what is the name of the reaction?

(a) Friedel-Craft’s reaction

(b) Hofmann reaction

(c) Hoffmann bromamide degradation reaction

(d) Hinsberg reaction

Ans. (c)

62. Which test can tell the difference between p-chloroaniline and anilinium hydrochloride?

(a) Sandmeyer reaction

(b) Carbylamine test

(c) AgNO₃

(d) NaHCO₃

Ans D

63. By reacting with which of the following, primary amines can be separated from secondary and tertiary amines?

(a) Chloroform alone

(b) Methyl iodide

(c) Chloroform and alcoholic KOH

(d) Zinc dust

Ans. (c)

64. Which of the following statements concerning methylamine is correct?

(a) Methylamine is stronger base than NH₃

(b) Methylamine is less basic than NH₃

(c) Methylamine is slightly acidic

(d) Methylamine forms salts with alkali

Ans. (a)

65. Sucrose is a chemical, and the hydrolysis product combination is in nature.

(a) dextrorotatory; dextrorotatory

(b) laevorotatory; laevorotatory

(c) laevorotatory; dextrorotatory

(d) dextrorotatory; laevorotatory

Ans. (d)

66. Which of the following statements about maltose is incorrect?

(a) It consists of two glucopyranose units

(b) It is a disaccharide

(c) Glycosidic bond between C1 of one unit and C4 of the other unit

(d) It is a non-reducing sugar

Ans. (d)

67. Which of the following statements about starch is incorrect?

(a) It gives blue colour with iodine

(b) It is a polymer of a-D-glucose

(c) It is a reducing carbohydrate

(d) It consists of branched chains

Ans. (c)

68. RNA lacks the nitrogen base of ………

(a) Thymine

(b) Cytosine

(c) Uracil

(d) Adenine

Ans. (a)

69. When converting a disaccharide to monosaccharides, which bond is hydrolyzed?

(a) Disulfide bond

(b) Glycosidic bond

(c) Phosphodiester bond

(d) Hydrogen bond

Ans. (b)