Oxygen and Sulphur MCQs [Chemistry]

By: Prof. Dr. Fazal Rehman | Last updated: May 23, 2025

1. : The common oxidation states of group IVA elements are
(A) +4 only
(B) +2, +4
(C) +4, +6
(D) +6 only

2. : HS acts as what kind of agent?
(A) Chlorinating agent
(B) Oxidizing agent
(C) Reducing agent
(D) None of A, B, and C

3. : What is the commonly used catalyst in the manufacture of H2SO4?
(A) Fe2O3 with a little CuO
(B) V₂O5
(C) Platinized asbestos and MgSO4
(D) All A, B, and C

4. : What are the geometry and dipole moment of O3?
(A) Angular and non-zero
(B) Angular and zero
(C) Linear and zero
(D) Linear and non-zero

5. : Molecule of oxygen is __________.
(A) Paramagnetic
(B) Diamagnetic
(C) Ferromagnetic
(D) None of A, B, and C

6. : What is the oxidation number of S in H2S?
(A) +2
(B) +1
(C) 1
(D) -2

7. : SO2 acts as what kind of acid or base?
(A) Lewis acid
(B) Lewis base
(C) Hard acid
(D) Hard base

8. : What is the structure of SO2?
(A) V-shaped
(B) Angular
(C) Linear
(D) Planar

9. : The gaseous mixture of N2O and O2 is used as _____.
(A) Fuel
(B) Anesthetic
(C) Oxidizing agent
(D) Reducing agent

10. : The H₂SO₄ gained by the contact process has purity of
(A) 70%
(B) 74%
(C) 82%
(D) 78%

11. : The contact process is generally used when acid is required for the manufacture of _________.
(A) Lead accumulators
(B) Fine chemicals
(C) Explosives
(D) All A, B, and C

12. : The specific gravity of H2SO4 is
(A) 1.84
(B) 1.37
(C) 1.17
(D) 1.57

13. : When H₂SO4 is used?
(A) In the dental filling
(B) In the purification of gold and silver
(C) In the preparation of aqua regia
(D) None of A, B, and C

14. : Perdisulphuric acid is ______ .
(A) H-acid
(B) Caro acid
(C) Marshal
(D) None of A, B, and C

15. : Black and white photographic film contain small grains of which of the following?
(A) Silver chloride
(B) Silver bromide
(C) Silver iodide
(D) Any of A, B, and C

16. : Which electronic configuration belongs to an element of group 16?
(A) [He] 2s2 2p2
(B) [Ar] 3d10 4s2 4p6
(C) [Ar] 3d5 4s1
(D) [Ne] 3s2 3p4

17. : O2 molecule is ___ .
(A) Paramagnetic
(B) Ferromagnetic
(C) Ferrmagnetic
(D) Diamagnetic

18. : Thermal stability of hydrides of group 16 elements decreases in the following order.
19. : Which types of halides are formed by members of group IVA?
(A) MX2
(B) MX4
(C) MX6
(D) All A, B, and C

20. : How many elements are in Group IVA?
(A) 5
(B) 4
(C) 3
(D) 6

21. : What is the electronegativity of oxygen?
(A) 3.5
(B) 2.5
(C) 5.3
(D) 2.1

22. : Which of the mentioned is not true for ozone?
(A) It is a strong sterilizing agent
(B) It attacks organic compounds containing carbon-carbon double bond
(C) Its molecular is linear and has two different 0-0 bond lengths
(D) It is more powerful oxidizing agent than molecular oxygen

23. : What trend is observed in ionization energy of group IVA elements down the group?
(A) Increases down the group
(B) First decreases then increases down the group
(C) Decreases down the group
(D) Remains constant

24. : Which compound is formed when S is boiled with Na2SO3 solution?
(A) Na2S2O3
(B) Na2SO4
(C) Na2S2O8
(D) Na2S

25. : What is the final acid gained during the manufacturing of sulfuric acid?
(A) Concentrated H2SO4
(B) H2S2O7
(C) Dilute H2SO4
(D) H2S2O6

26. : Which of the mentioned is wrong?
(A) H2O2 is a planar molecule
(B) Water is more polar than H₂S
(C) Heavy water is produced by the exhaustive electrolysis of water made acidic
(D) H2O2 acts both as oxidizing as well as reducing agent in acidic medium

27. : Oxalic acid when heated with conc. H₂SO4 it gives out
(A) H₂O and CO2
(B) Oxalic sulphate
(C) CO2 and H2S
(D) CO and CO₂

28. : Select the wrong statement for SO2
(A) It turns filter paper moistened with acidified K2Cr2O7
(B) It turns starch iodate paper blue
(C) It does not react with chlorine in presence of charcoal
(D) It decolorizes acidified KMnO4 solution

29. : B.P of heavy water is __________.
(A) Equal to that of ordinary water
(B) Less than that of ordinary water
(C) Greater than that of ordinary water
(D) Equal to that of distilled water

30. : Ozone is not ______.
(A) An allotrope
(B) A powerful oxidizing agent
(C) A bent molecule
(D) Paramagnetic

31. : Which of the mentioned statements about the manufacture of H2SO4 by contact process is not true?
(A) S is burnt in air to form SO2
(B) SO2 is oxidized to SO3 in presence of V2O5 as catalyst (or finely divided spongy platinum as catalyst) at a pressure of 2 atm and temperature of about 700 K
(C) SO3 is dissolved in H2O to get 100% H2SO4 acid
(D) H2SO4 gained by contact process is of higher purity than that gained by lead chamber process

32. : The hybridization of S in SO2 is
(A) sp
(B) sp3
(C) dsp2
(D) sp2

33. : Which one of the following has the highest boiling point?
(A) H₂S
(B) H₂O
(C) H₂Se
(D) H₂Te

34. : Which of the mentioned compounds is most acidic?
(A) H₂O
(B) H₂S
(C) H₂Te
(D) H₂Se

35. : Which of the mentioned represents the fuming sulphuric acid (oleum or pyrosulphuric acid)?
(A) H2S2O7
(B) H2S2O3
(C) H₂S₂O8
(D) H2S2O4

36. : Hypo is used in photography to
(A) Remove undecomposed silver bromide as soluble complex
(B) Remove silver as silver salt
(C) Reduce AgBr to metallic silver
(D) Remove reduced silver

37. : Select the ideal conditions required for the manufacture of H2SO4 by contact process.
(A) Low temperature, high pressure and high concentration of reactants
(B) Low temperature, low concentration of reactants and low pressure
(C) High temperature, high pressure and high concentration of reactants
(D) Low temperature, low pressure and high concentration of reactants

38. : Ozone is an important constituent of stratosphere, because it
(A) Prevents the formation of smog over large cities
(B) Removes poisonous gases of the atmosphere by reacting with them
(C) Destroys bacteria, which are harmful to human life
(D) Absorbs ultraviolet radiation, which is harmful to human life

39. : Which of these is a type of qualitative analysis?
(A) Macro-analysis
(B) Micro-analysis
(C) Semi-microanalysis
(D) All A, B, and C

40. : What do you expect if the given salt mixture is crystalline and light?
(A) May be heavy metals salt
(B) May be halides of Ca, Fe, Zn etc
(C) May be phosphate of Mg, Zn etc
(D) May be alkali metal salt

41. : What do you expect if the given salt mixture is colorless and heavy?
(A) May be heavy metals salt
(B) May be alkali metal salt
(C) May be phosphate of Mg, Zn etc
(D) May be halides of Ca, Fe, Zn etc

42. : What do you expect if the given salt mixture is colorless?
(A) Cu and Cr salts are absent
(B) Ni and Co salts are absent
(C) Mn and Fe salts are absent
(D) All A, B, and C are absent

43. : What do you expect if the given salt mixture is dark green?
(A) Cr salts are present
(B) Ni salts are present
(C) Cu salts are present
(D) Mn salts are present

44. : What do you expect if the given salt mixture is blue?
(A) Cr salts are present
(B) Ni salts are present
(C) Cu salts are present
(D) Mn salts are present

45. : What do you expect if the odor of the given salt mixture is vinegar-like?
(A) Carbonates are present
(B) Acetates are present
(C) Sulfides are present
(D) Nitrates are present

46. : What do you expect if the given salt mixture evolves reddish brown fumes with pungent smell on treatment with dil. sulfuric acid?
(A) Carbonates are present
(B) Acetates are present
(C) Sulfides are present
(D) Nitrites are present

47. : What do you expect if the given salt mixture evolves colorless gas with rotten egg’s smell on treatment with dil. sulfuric acid?
(A) Carbonates are present
(B) Acetates are present
(C) Sulfides are present
(D) Nitrites are present

48. : What do you expect if the given salt mixture evolves colorless gas with pungent smell on treatment with dil. sulfuric acid?
(A) Acetates are present
(B) Sulphites and thiosulfates
(C) Sulfides are present
(D) Nitrites are present

49. : What do you expect if the given salt mixture evolves colorless gas which turns lime water milky on treatment with dil. sulfuric acid?
(A) Carbonates and bicarbonates are present
(B) Acetates are present
(C) Sulfides are present
(D) Nitrites are present

50. : What do you expect if the given salt mixture evolves violet vapors with pungent smell on treatment with con. sulfuric acid?
(A) Iodides are present
(B) Acetates are present
(C) Bromides are present
(D) Nitrates are present

51. : The group reagent for group IIIA is
(A) Dil. HNO₃
(B) NH₄Cl
(C) NH₄Cl + NH₄OH
(D) Dil. HCl

52. : The group reagent for group IVA is
(A) Dil. HNO₃
(B) NH₄Cl
(C) Dil. HCl
(D) NH₄Cl + NH₄OH + H₂S

53. : Which of these statements is wrong with regard to usual hazards in chemical lab?
(A) Alkali metals are safe
(B) Organic solvents are toxic
(C) Strong acids are toxic
(D) Strong bases are extremely

54. : Which of these statements is wrong with regard to usual hazards in chemical lab?
(A) Strong alkylating agents are toxic
(B) Gas cylinders cause no harm
(C) Oxidizing agents react violently
(D) Glassware may cut your skin

55. : Which of these chemicals is carcinogenic in nature?
(A) Polycyclic aromatics
(B) Cyanides
(C) Arsenic
(D) All A, B, and C

56. : Which member of the group IV is colorless?
(A) Zn²⁺
(B) Ni²⁺
(C) Cu²⁺
(D) Mn²⁺

57. : Which of these statements is not true regarding primary standard?
(A) It is easily available in state of purity
(B) It is readily soluble in water
(C) It is hygroscopic in nature
(D) Its solution is stable

58. : Titrations involving oxidation and reduction reactions are called
(A) Redox titration
(B) Iodometry
(C) Argentometry
(D) Complexometry

59. : Which of these reagents are helpful and used as oxidizing agents?
(A) KMnO₄
(B) Potassium bromate
(C) K₂Cr₂O₇
(D) All A, B, and C

60. : Which of these reagents are helpful and used as reducing agents?
(A) Na₂S₂O₃
(B) KMnO₄
(C) Potassium bromate
(D) K₂Cr₂O₇