Chemistry MCQs Set 2 Frequently Asked Questions in Exams

This section contains chemistry MCQs designed to test your chemistry knowledge and aid in your preparation for competitive exams. Practicing these questions enhances comprehension of fundamental chemistry principles and boosts exam performance. It’s worth noting that these questions are frequently asked in various exams, making them an excellent resource for exam preparation.

1. What determines the strength of an acid?
a. Kw
b. Ka
c. Kp
d. Kc
Answer: b. Ka

2. A high value of Ka indicates that the acid is:
a. Weak
b. Strong
c. Very weak
d. Very strong
Answer: d. Very strong

3. The sum of pKa and pKb is equal to:
a. 7
b. 2
c. 1
d. 14
Answer: d. 14

4. Among halogen acids, the strongest acid is:
a. HCl
b. HI
c. HF
d. HBr
Answer: b. HI

5. According to the Arrhenius concept, which of the following is not considered an acid?
a. HCl
b. H2SO4
c. NH3
d. HNO3
Answer: c. NH3

6. Who is credited with the concept that an acid is a proton (H⁺) donor and a base is a proton acceptor?
a. Lux Flood
b. Arrhenius theory
c. Bronsted Lowry
d. Albert Hofmann
Answer: c. Bronsted Lowry

7. Bases and reducing agents are electron-donating agents and are also known as?
a. Electrodotic
b. Nucleophile
c. Electrophile
d. Bronsted-Lowry bases
Answer: b. Nucleophile

8. According to the Lewis concept, which of the following substances can act as a Lewis acid?
a. Water (H2O)
b. Ammonia (NH3)
c. Boron trichloride (BCl3)
d. Sodium hydroxide (NaOH)
Answer: c. Boron trichloride (BCl3)

9. The Lux-Flood concept is a donor-acceptor of:
a. Proton
b. Oxide ion
c. Neutron
d. Electron pair
Answer: b. Oxide ion

10. Which concept is synonymous with the electron pair donor-acceptor system?
a. Bronstead Lowry theory
b. Lewis theory
c. Usanovich theory
d. Lux Flood theory
Answer: b. Lewis theory

11. Which of the following is the most convenient and has the nearest approach to a universal pH measurement?
a. pH string
b. pH indicator
c. The emf method
d. The calorimeter
Answer: c. The emf method

12. What is the typical pH of milk?
a. 6.0
b. 7.0
c. 6.5
d. 7.5
Answer: c. 6.5

13. What is the pH of pure water at 25°C?
a. Highly acidic
b. Slightly acidic
c. Neutral
d. Slightly basic
Answer: c. Neutral

14. Identify the reaction that deviates from the Arrhenius concept of acids and bases:
a. HCl(g) + NH3(g) → NH4Cl(s)
b. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
c. HClO4(aq) + H2O(l) → H3O+(aq) + ClO4-(aq)
d. H3O+(aq) + OH-(aq) → 2H2O(l)
Answer: a. HCl(g) + NH3(g) → NH4Cl(s)

15. What is the pH of the solution obtained by mixing 100 mL of a pH 1 strong acid with 100 mL of a pH 2 strong acid?
a. 3.5
b. 2.26
c. 2.0
d. 1.26
Answer: d. 1.26

16. In which of the following reactions does H2PO4– act as an acid?
a. H3PO4 + H2O → H3O+ + H2PO4–
b. H2PO4– + H2O → HPO42– + H3O+
c. H2PO4– + OH–→ H3PO4 + O2-
d. H3O+ + OH–→ 2H2O
Answer: b. H2PO4– + H2O → HPO4^2– + H3O+

17. Which of the following is commonly used as an olfactory indicator?
a. China rose
b. Methyl orange
c. Lemon
d. Onion
Answer: d. Onion

18. Among the following species, which one can function as both a Bronsted acid and a Bronsted base?
a. H2SO4
b. OH-
c. HSO-4
d. NH3
Answer: c. HSO-4

19. The pH of a solution resulting from the combination of 100 mL of 0.20 M weak acid HA (Ka = 10^-5) and 100 mL of 0.20 M NaOH at room temperature is:
a. 6
b. 9
c. 8
d. 7
Answer: b. 9

20. What is the pH of a solution formed by dissolving 0.005 moles of Ca(OH)2 in 50 mL of water?
a. 10.5 approx.
b. 13 approx.
c. 8.2 approx.
d. 15 approx.
Answer: b. 13 approx.

21. Which of the following is not a common use of Bleaching powder?
a. Used in soda-acid fire extinguishers
b. Bleaching agent
c. Oxidizing agent
d. Disinfectant
Answer: a. Used in soda-acid fire extinguishers

22. When sodium hydrocarbonate solution is heated, what is the resulting product?
a. Ammonium chloride (NH4Cl)
b. Sodium nitrate (NaNO3)
c. Sodium carbonate (Na2CO3)
d. Sodium carbonate decahydrate (Na2CO3.10H2O)
Answer: c. Sodium carbonate (Na2CO3)

23. What is the ratio of water molecules in plaster of Paris to gypsum?
a. 1:4
b. 3:1
c. 1:3
d. 4:3
Answer: a. 1:4

24. What is the composition of baking powder?
a. Sodium carbonate + sodium tartaric
b. Sodium carbonate + tartaric acid
c. Sodium bicarbonate + sodium tartaric
d. Sodium carbonate + sodium benzoate
Answer: c. Sodium bicarbonate + sodium tartaric

25. Which acid is employed in the production of fertilizers and explosives?
a. Sulfuric acid
b. Phosphoric acid
c. Nitric acid
d. Hydrochloric acid
Answer: c. Nitric acid

26. What is a species that can act as both a Bronsted acid and a Bronsted base called?
a. Amphoteric
b. Neutral
c. Inert
d. Catalyst
Answer: a. Amphoteric

27. In the equation: HF + H2O ⇌ H3O+ + F-
Which statement correctly describes the roles of the species involved?
a. H2O is a base and HF is its conjugate acid
b. H2O is an acid and HF is the conjugate base
c. HF is a base and H3O+ is its conjugate acid
d. HF is an acid and F- is its conjugate base
Answer: d. HF is an acid and F- is its conjugate base

28. For the reaction of nitric acid with aluminum hydroxide, which of the following represents the correct net ionic equation?
a. H+ + OH- → H2O
b. HNO3 + Al(OH)3 → Al(NO3)3 + 3H2O
c. 3H+ + Al(OH)3 → Al3+ + 3H2O
d. HNO3 + OH- → NO3- + H2O
Answer: c. 3H+ + Al(OH)3 → Al3+ + 3H2O

29. Which of the following metal hydroxides exhibits amphoteric behavior?
a. NaOH
b. Ba(OH)2
c. Pb(OH)2
d. LiOH
Answer: c. Pb(OH)2

30. What is the pH of a 0.001 M solution of hydrochloric acid (HCl)?
a. 1
b. 7
c. 3
d. 2
Answer: c. 3

31. Which enzyme does not participate in the starch fermentation process?
a. Diastase
b. Zymase
c. Urease
d. Invertase
Answer: c. Urease

32. Methyl alcohol is not commonly employed as:
a. A solvent
b. An anti-freeze agent
c. A substitute for petrol
d. For denaturing of ethyl alcohol
Answer: c. A substitute for petrol

33. What is the alcohol content in rectified spirit?
a. 80%
b. 85%
c. 90%
d. 95%
Answer: d. 95%

34. According to the Lewis concept, what can ethers be classified as?
a. Lewis acids
b. Lewis bases
c. Lewis salts
d. Lewis catalysts
Answer: b. Lewis bases

35. How can ethanol be converted into ethanoic acid?
a. Esterification
b. Hydration
c. Oxidation
d. Fermentation
Answer: c. Oxidation

36. What is the common name for a phenol-formaldehyde resin?
a. Bakelite
b. Teflon
c. Melamine
d. Polyester
Answer: a. Bakelite

37. The phenol-formaldehyde resins are formed by polymerization of phenol and formaldehyde through:
a. Condensation polymerization
b. Addition polymerization
c. Copolymerization
d. Polycondensation
Answer: a. Condensation polymerization

38. Methanol (CH3OH), also known as:
a. Wood spirit
b. Methylated spirit
c. Rectified spirit
d. Absolute alcohol
Answer: a. Wood spirit

39. Among the following compounds, which has a higher boiling point?
a. Methanol
b. Ethanol
c. Methyl chloride
d. Glycol
Answer: d. Glycol

40. Which type of reactions are readily undergone by phenols?
a. Nucleophilic substitution
b. Electrophilic substitution
c. Electrophilic addition
d. Nucleophilic addition
Answer: b. Electrophilic substitution

41. Why is phenol acidic in nature?
a. Presence of a carbonyl group
b. Aromatic ring structure
c. Presence of a hydroxyl group
d. High boiling point
Answer: c. Presence of a hydroxyl group

42. Partial hydrogenation of phenol results in the formation of:
a. Cyclohexanone
b. Cyclohexene
c. Benzoic acid
d. Benzene
Answer: a. Cyclohexanone

43. Which enzyme is derived from germinated barley, known as malt?
a. Zymase
b. Maltase
c. Diastase
d. Invertase
Answer: c. Diastase

44. Among the following, which type of alcohol has the highest boiling point?
a. Primary alcohol
b. Secondary alcohol
c. Tertiary alcohol
d. None of these
Answer: a. Primary alcohol

45. When a nucleophile attacks, which bond typically breaks?
a. C-X bond
b. O-H bond
c. C-C bond
d. H-X bond
Answer: a. C-X bond

46. Ethers, specifically R-O-R ethers, are most reactive with which of the following?
a. Hydrochloric acid (HCl)
b. Hydrobromic acid (HBr)
c. Hydrofluoric acid (HF)
d. Hydroiodic acid (HI)
Answer: d. Hydroiodic acid (HI)

47. Which of the following statements about Ethers is false?
a. Ethers have a bent molecular geometry
b. Ethers can be used as solvents
c. Ethers are generally more soluble in water than alcohols
d. Ethers do not form hydrogen bonds with water
Answer: c. Ethers are generally more soluble in water than alcohols

48. Which of the following alcohols exhibits both primary and secondary alcohol characteristics?
a. Methanol
b. Ethanol
c. Isopropanol
d. Butanol
Answer: c. Isopropanol

49. Among the following phenols, which one does not exhibit resonance stabilization in its aromatic ring?
a. Phenol
b. Resorcinol
c. Catechol
d. Hydroquinone
Answer: d. Hydroquinone

50. Among the following compounds, which one would NOT react with Lucas reagent at room temperature?
b. (CH3)3COH
c. C6H5CH2OH
Answer: a. CH3CH2CH2OH

51. Which functional group can be found in both alcohols and phenols but not in ethers?
a. Hydroxyl (OH)
b. Alkyl (R)
c. Aryl (Ar)
d. Ether (R-O-R)
Answer: a. Hydroxyl (OH)

52. In a reaction between benzenediazonium chloride and phenol in a weakly basic medium, the product formed is:
a. p-hydroxyazobenzene
b. Diphenyl ether
c. Chlorobenzene
d. Benzene
Answer: a. p-hydroxyazobenzene

53. Phenol’s reaction with bromine in CS2 at low temperatures primarily yields:
a. m-bromophenol
b. p-bromophenol
c. 2,4,6-tribromophenol
d. o-and p-bromophenol
Answer: d. o-and p-bromophenol

54. What is the product formed when phenol reacts with excess bromine water?
a. m-bromophenol
b. p-bromophenol
c. 2,4,6-tribromophenol
d. o-and p-bromophenol
Answer: c. 2,4,6-tribromophenol

55. The product of the reduction of phenol with H2 in the presence of a Ni catalyst is:
a. Benzene
b. Cyclohexanol
c. Toluene
d. Cyclohexane
Answer: b. Cyclohexanol

56. The dehydration of alcohol is an example of which type of reaction?
a. Addition reaction
b. Substitution reaction
c. Elimination reaction
d. Redox reaction
Answer: c. Elimination reaction

57. What is the compound obtained by the reaction of ethene with diborane followed by hydrolysis with alkaline H2O2?
a. Ethanal
b. Propanol
c. Triethyl bromide
d. Ethanol
Answer: d. Ethanol

58. When glycerol is heated with oxalic acid at 230 °C, which compound is formed?
a. Acrolein
b. Glyceric acid
c. Methanoic acid
d. Allyl alcohol
Answer: d. Allyl alcohol

59. Among the following alcohols, which one does not react with Lucas reagent at room temperature?
a. Isobutyl alcohol
b. tert-butyl alcohol
c. n-butanol
d. sec-butyl alcohol
Answer: c. n-butanol

60. Which of the following reactions represents the formation of an ether through the Williamson synthesis?
a. CH3OH + NaOH → CH3ONa + H2O
b. C6H5OH + NaH → C6H5ONa + H2O
c. CH3CH2OH + NaOH → CH3CH2ONa + H2O
d. CH3CH2Br + C6H5OH → CH3CH2OC6H5 + HBr
Answer: d. CH3CH2Br + C6H5OH → CH3CH2OC6H5 + HBr