Nitrogen and Phosphorus MCQs [Chemistry]

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

1. : Hydrolysis of PCl3 gives
(A) H3PO3
(B) H4P2O6
(C) H3PO2
(D) H4P2O7

2. : Hydrolysis of PCl5 gives
(A) H4P2O6
(B) H3PO4
(C) H3PO2
(D) H4P2O7

3. : What is the common oxidation state of elements of group VA?
(A) +5
(B) +3
(C) -3
(D) Any of A, B, and C

4. : Which of the mentioned molecule is diatomic?
(A) Phosphorous
(B) Nitrogen
(C) Arsenic
(D) Antimony

5. : Artificial nitrogen fixation may occur by the formation of ________.
(A) Nitric acid
(B) Nitrates
(C) Ammonia
(D) Any of A, B, and C

6. : Which is a colorless gas with pleasant odor and sweet taste?
(A) N2O3
(B) N2O
(C) NO
(D) N2O4

7. : Which of the mentioned statements is not true about this group?
(A) Electronegativity increases down the group
(B) Metallic character increases down the group
(C) There is steady increase in atomic radii down the group
(D) There is an increase in hardness from P to Bi

8. : Group VA of the periodic table consists of how many elements?
(A) 3
(B) 5
(C) 7
(D) 2

9. : Which elements are non-metals?
(A) N & P
(B) As & Sb
(C) Sb & Bi
(D) Ba & Bi

10. : Which of the mentioned members are solid in nature?
(A) P
(B) Sb
(C) As
(D) All of A, B, and C

11. : Polyphosphates are helpful and used as water softening agents because they
(A) form soluble complexes with anionic species
(B) form soluble complexes with cationic species
(C) precipitate cationic species
(D) precipitate anionic species

12. : Which of the mentioned elements shows least ionization potential?
(A) As
(B) Bi
(C) Sb
(D) N

13. : Nitric acid is helpful and used in the manufacturing of
(A) Artificial silk
(B) Drugs
(C) Dyes
(D) All of A, B, and C

14. : Among oxides of nitrogen, all are gases excluding ___ .
(A) N2O5
(B) N2O
(C) NO
(D) N2O3

15. : In Ostwald’s process of manufacturing nitric acid a mixture of ammonia gas with air is maintained with ________ ratio.
(A) 1:4
(B) 1:8
(C) 2:4
(D) 3:5

16. : Acid rain affects _____.
(A) Aquatic life
(B) Crops
(C) Human beings
(D) All of A, B, and C

17. : What is the formula of orthophosphoric acid?
(A) H3P2O5
(B) H3PO3
(C) H3PO2
(D) H3PO4

18. : What is the % purity of commercial phosphoric acid?
(A) 82.98%
(B) 37.0%
(C) 98.2%
(D) 90.12%

19. : Urea belongs to what kind of fertilizer?
(A) Nitrogen fertilizer
(B) Potash fertilizer
(C) Phosphorous fertilizer
(D) Complete fertilizer

20. : In urea the amount of nitrogen is
(A) 16.0%
(B) 82.0%
(C) 33.0%
(D) 21.0%

21. : Ammonia is utilized for __________.
(A) Manufacture of ammonium sulphate
(B) Oxidation to nitric acid
(C) Manufacture of urea
(D) All of A, B, and C

22. : Which of the mentioned is a strong base?
(A) AsH3
(B) SbH3
(C) PH3
(D) NH3

23. : Nitrogen (N2) is relatively unreactive, because
(A) Its electronegativity is high
(B) Its atomic radius is small
(C) Its dissociation energy is large
(D) It is the first element of group 15

24. : Phosphorus normally exhibits a covalence of ___ and ___ .
(A) +3 and +5
(B) +2 and +3
(C) +3 and +4
(D) +1 and +2

25. : Which of the mentioned elements occurs in free state in nature?
(A) P
(B) Sn
(C) N
(D) Sb

26. : Which of the mentioned pentahalides is not formed?
(A) NF3
(B) PF3
(C) AsF3
(D) BiF3

27. : The accurate order of thermal stabilities of hydrides of group 15 is
28. : Arrange the hydrides of group 15 in the accurate order of reducing nature.
(A) NH3 < PH3 < AsH3 < SbH3 < BiH3
(B) NH3 > PH3 > AsH3 > SbH3 > BiH3
(C) PH3 < AsH3 < SbH3 < BiH3 < NH3
(D) PH3 > AsH3 > SbH3 > BiH3 > NH3

29. : Which of the mentioned oxides of nitrogen is a colored gas?
(A) NO2
(B) NO
(C) N2O
(D) N2O5

30. : The basic strength of hydrides of group 15 elements vary in the following order
31. : Which of the following trihalides of nitrogen behaves as the weakest base?
(A) NI3
(B) NCl3
(C) NBr3
(D) NF3

32. : Which trihalide is not hydrolyzed by water?
(A) NF3
(B) NCl3
(C) PCl3
(D) AsCl3

33. : Which catalyst is helpful and used in Contact process?
(A) SO3
(B) FeO
(C) N2O3
(D) V2O5

34. : Select the false statement.
(A) In PCl5, P atom is sp³d-hybridized and has trigonal bipyramidal geometry.
(B) PCl5 on hydrolysis forms phosphoric acid
(C) PCl5 acts as Lewis acid
(D) In PCl5, the axial chlorine atoms are closer to central ‘P’ atom than equatorial chlorine atoms

35. : Arrange the oxides of group 15 elements in decreasing order of their acidity.
36. : In which of the mentioned compounds the oxidation state of N is +1?
(A) N2O2
(B) NO2
(C) N2O4
(D) NO

37. : Which of the mentioned acids possesses oxidizing, reducing and complex forming properties?
(A) H2SO4
(B) HCl
(C) HNO3
(D) HNO2

38. : Which of the mentioned elements of group 15 is a typical metal?
(A) P
(B) Bi
(C) Sb
(D) As

39. : Which of the mentioned elements display maximum tendency to form pπ multiple bonds with itself and with carbon and oxygen?
(A) Bi
(B) P
(C) As
(D) N

40. : Which of the mentioned acids have P atom existing in lower oxidation state?
(A) H3PO4
(B) H3PO2
(C) H3PO3
(D) H4P2O7

41. : Which of the mentioned does not form stable diatomic molecule?
(A) Nitrogen
(B) Hydrogen
(C) Phosphorus
(D) Oxygen

42. : The oxidation states shown by phosphorus is/are
(A) -3
(B) +3
(C) +3 and +5
(D) -3, +3 and +5

43. : White phosphorus is usually kept under
(A) Ammonia liquor
(B) Cold water
(C) Ethanol
(D) Kerosene

44. : Which of the mentioned statement is true?
(A) PH3 is more basic than ammonia
(B) NH3 is amphoteric and PH3 is basic
(C) PH3 is equally basic as ammonia
(D) PH3 is less basic than ammonia

45. : Nitric acid can be prepared by
(A) From sodium nitrate and sulfuric acid
(B) Birkland tyde process
(C) Ostwald’s process
(D) All of A, B, and C

46. : Ostwald’s process for the manufacture of HNO3 involves the
(A) Oxidation of N2 to NO
(B) Oxidation of NH3 to NO in presence PU/Rh catalyst
(C) Combination of N2 and O2
(D) Combination of H2O and N2O5

47. : The strongest acid is
(A) HNO3
(B) HNO2
(C) H2N2O2
(D) Any of these

48. : Phosphorus has the oxidation state of +3 in
(A) Orthophosphoric acid
(B) Hypophosphoric acid
(C) Orthophosphorus acid
(D) Metaphosphoric acid

49. : The Ostwald process is the main method for the manufacture of nitric acid. In the first step in this process is
(A) Nitrogen and hydrogen react to form NH3
(B) Ammonia is burned in O2 to generate N2 and H2O
(C) Nitrogen and oxygen react to form NO2
(D) Ammonia is burned with O2 to generate NO and H2O

50. : Which of the mentioned oxyacids of P contains maximum number of P-H bonds?
(A) H3PO4
(B) H3PO3
(C) H3P2O7
(D) H3PO2

51. : Which of the mentioned acids have P atom existing in highest oxidation state?
(A) H4P2O7
(B) H3PO3
(C) H3PO2
(D) H4P2O6

52. : Hydrolysis of P4O10 with excess of water gives _____.
(A) H4P2O6
(B) H3PO4
(C) H3PO2
(D) H4P2O7

53. : Which of the mentioned elements shows catenation?
(A) As
(B) Bi
(C) Sb
(D) N

54. : Aqua regia is made by dissolving a mixture of HNO3 and HCl with ____ ratio.
(A) 1:3
(B) 2:1
(C) 1:2
(D) 1:1

55. : Nitric acid has the property of __.
(A) Reducing
(B) Nitrating
(C) Redoxing
(D) Any of these

56. : Nitric acid is helpful and used in manufacturing of _____.
(A) Fertilizer
(B) H2SO4
(C) Explosive
(D) All of A, B, and C