P – BLOCK ELEMENTS – 10

1) The basicity of orthophosphoric acid is
a) 2
b) 3
c) 4
d) 5

2) reacts with water to form
a)
b)
c)
d)

3) is heated with water to give
a) Hypophosphoric acid
b) Orthophosphoric acid
c) Hypophosphorous acid
d) Orthophosphorous acid

4) Which of the following reacts rapidly with oxygen in the air at ordinary temperature ?
a) White P
b) Red P
c)
d)

5) Phosphine is produced by adding water to
a)
b)
c)
d)

6) By the action of hot conc., phosphorus changes to
a) Phosphorous acid
b) Orthophosphoric acid
c) Metaphosphoric acid
d) Pyrophosphoric acid

7) is the formula for one of the phosphorus acids. Its name and basicity are respectively
a) Phosphorous acid and two
b) Hypophosphorous acid and two
c) Hypophosphorous acid and one
d) Hypophosphorous acid and two

8) Which of the following types of phosphorus is most stable ?
a) Red
b) White
c) Black
d) All are stable

9) P4O10 has short and long P-O bonds. The number of short P-O bonds in this compound is
a) 1
b) 2
c) 3
d) 4

10) The number of hydroxyl groups in pyrophosphoric acid is
a) 3
b) 4
c) 5
d) 7

11) The crystalline form of sulphur which is stable at room temperature is
a) Rhombic sulphur
b) Monoclinic sulphur
c) Plastic sulphur
d) Prismatic sulphur

12) Phosphine is not obtained by the reaction when
a) White P is heated with NaOH
b) Red P is heated with NaOH
c)
d) Phosphorous trioxide is boiled with water

13) The structure of PCl5 is
a) Octahedral
b) Trigonal bipyramidal
c) Tetrahedral
d) Pyramidal

14) The sides of a match box have a coating of
a) Potassium chlorate and red lead
b) Potassium chlorate and antimony sulphide
c) Antimony sulphide and red phosphorus
d) Antimony sulphide and red lead

15) RRR The structure of the PF5 molecule is
a) Tetrahedral
b) Square planar
c) Trigonal bipyramidal
d) Pentagonal bipyramidal

16) The acid which forms two series of salts is
a)
b)
c)
d)

17) Which of the following is a cyclic phosphate ?
a)
b)
c)
d)

18) Calcium cyanamide on treatment with steam under pressure gives
a)
b)
c)
d)

19) In the P3-,S2- and Cl ions the increasing order of size is
a)
b)
c)
d)

20) PCl3 on hydrolysis gives
a)
b)
c)
d)

21) Arrange the following in order of increasing acidity:
a)
b)
c)
d)

22) White phosphorus + Caustic soda Phosphine + NaH2PO2

The above reaction is

a) Oxidation reaction
b) Reduction reaction
c) Neutralization
d) Redox reaction

23) The structural formula of hypophosphoric acid is
a)
b)
c)
d)

24) The oxyacid of phosphorus in which P has the lowest oxidation state is
a) Metaphosphoric acid
b) Orthophosphoric acid
c) Pyrophosphoric acid
d) Hypophosphoric acid

25) Repeated use of which one of the following fertilizers would increase the acidity of the soil ?
a) Urea
b) Potassium nitrate
c) Ammonium sulphate
d) Superphosphate of lime.

26) Which of the following is not an acid salt ?
a)
b)
c)
d) None of these

27) One mole of calcium phosphide on reaction with excess water gives
a) One mole of phosphine
b) Two moles of phosphoric acid
c) Two moles of phosphine
d) One mole of phosphorus pentoxide

28) Which forms a new compound in air ?
a)
b)
c)
d)

29) Which of the following is most reactive ?
a) Red phosphorus
b) White phosphorus
c) Scarlet phosphorus
d) Violet phosphorus

30) Which of the following is the correct statement for PH3 ?
a)
b)
c)
d) It does not show reducing properties

31) The number of P-O-P bonds in cyclic metaphosphoric acid is/are
a) zero
b) Two
c) Three
d) Four

32) Hybridisation in PCl5 is
a)
b)
c)
d)

33) Which one of the following is triple super phosphate ?
a)
b)
c)
d)

34) Which of the following does not exist ?
a)
b)
c)
d)

35) Bones glow in the dark. This phenomenon is called
a) Photoconductivity
b) Semiconductivity
c) Phosphorescence
d) None of these

36) White Phosphorus (P4) has
a) Six P-P single bonds
b) Four lone pairs of electrons
c) A P-P-P angle of 60 degrees
d) All are correct

37) Which of the following burns to form an oxide which is gaseous at room temperature ?
a) Hydrogen
b) Helium
c) Sodium
d) Sulphur

38) Which of the following is used to absorb sulphur dioxide ?
a)
b) KOH solution
c) Water
d)

39) The gas liberated when an aqueous solution of thioacetamide is heated is
a)
b)
c)
d)

40) Which of the following turns lead acetate paper black ?
a)
b)
c)
d)

41) A solution of sulphur dioxide in water reacts with precipitating sulphur. Here sulphur dioxide acts as
a) An oxidising agent
b) A reducing agent
c) An acid
d) A catalyst

42) When is passed through an acidified solution of
a)
b)
c) Sulphur is precipitated
d) None

43) A salt of sulphurous acid is called
a) Sulphate
b) Sulphurate
c) Sulphite
d) Sulphide

44) RRR The catalyst used for the oxidation of to in contact process for the manufacture of is
a) Finely divided iron
b) Molybdenum
c) Nitric oxide
d) Vanadium pentoxide

45) In the contact process, the impurities of arsenic are removed by
a)
b)
c)
d)

46) Which of the following statement regarding the manufacture of by contact process is not true ?
a)
b)
c) SO3 is dissolved in water to get 100% sulphuric acid
d)

47) The most favourable condition for the reaction,2SO2 + O2 2 SO3 + 98 KJ/mole is

a) High temperature and low pressure
b) High temperature and high pressure
c) Low temperature and low pressure
d) Low temperature and high pressure

48) In the reaction

acts as a/an

a) Dehydrating agent
b) Oxidising agent
c) Reducing agent
d) All the above

49) In the reaction

acts as a/an

a) Reducing agent
b) Oxidising agent
c) Catalytic agent
d) Dehydrating agent

50) Which of the following is used as a reagent in iodometric titrations ?
a)
b)
c)
d)

51) Which of the following statements regarding the thiosulphate ion is incorrect ?
a) The shape of the thiosulphate ion is tetrahedral
b) The two sulphur atoms in thiosulphate ion are equivalent
c) There is a S-S bond in thiosulphate ion
d) With iodine, the thiosulphate ion gives tetrathionate

52) The two sulphur atoms in have
a) +2 and +4 oxidation state
b) –2 and +6 oxidation states
c) +4 and +6 oxidation states
d) the same oxidation states

53) Sodium thiosulphate is formed when
a) NaOH is neutralised by sulphuric acid
b)
c)
d)

54) Sodium thiosulphate is formed when
a)
b)
c)
d) All the above

55) The bleaching action of is due to
a) Reduction
b) Oxidation
c) Hydrolysis
d) Its acidic nature

56) Which of the following is oxidised by ?
a) Mg
b)
c)
d) All the above

57) Which one is known as oil of vitriol ?
a)
b)
c)
d)

58) Which one of the gases below dissolves in to give oleum ?
a)
b)
c)
d)

59) When is passed through acidified solution
a) The solution turns blue
b) The solution is decolourised
c)
d)

60) Which oxide of nitrogen is used as a catalyst in the lead chamber process for the manufacture of ?
a) NO
b)
c)
d)

61) RRR When conc.H2SO4 comes in contact with sugar, it becomes black due to
a) Hydrolysis
b) Hydration
c) Decolourisation
d) Dehydration

62) When aluminium phosphide is treated with dil.sulphuric acid
a)
b)
c)
d)

63) Which of the following will give carbon on reacting with conc. H2SO4 ?
a) Sugar
b) Starch
c) Wood
d) All the above

64) The acid used in lead storage cells is
a) Phosphoric acid
b) Nitric acid
c) Sulphuric acid
d) Hydrochloric acid

65) The products of the chemical reaction between , and are
a)
b)
c)
d)

66) @ The chemical reaction between and in an aqueous medium produces
a)
b)
c)
d)

67) Iodine oxidises the ion to
a)
b)
c)
d)

68) There is no S-S bond in
a)
b)
c)
d)

69) Oleum is
a)
b)
c)
d)

70) The final acid obtained during the manufacture of by the contact process is
a)
b)
c)
d)

71) When sulphur is boiled with solution, the compound formed is
a) Sodium sulphide
b) Sodium sulphate
c) Sodium persulphate
d) Sodium thiosulphate

72) The constitution of superphosphate is
a) Gypsum and Calcium dihydrogen phosphate
b) Gypsum and Calcium phosphate
c)
d)

73) What is the product of the reaction shown below ?

a)
b) S
c)
d)

74) Which is incorrect about H2SO4? It is a
a) Reducing agent
b) Dehydrating agent
c) Sulphonating agent
d) Highly viscous

75) Sodium thiosulphate (Na2S2O3.5H2O) is used in photography to
a) Reduce silver bromide to metallic silver
b) Convert metallic silver to silver salt
c) Remove undecomposed AgBr as a soluble silver thiosulphate
d) Remove reduced silver

76) In the reaction H2S2H+ + S2- ,when NH4OH is added, the
a)
b) No action takes place
c)
d)

77) Which is an oxidising substance amongst the following ?
a)
b)
c)
d)

78) When oxalic acid is dehydrated by conc. H2SO4, it forms
a)
b) CO
c)
d)

79) Which of the following behaves as both oxidising and reducing agent ?
a)
b)
c)
d)

80) @ If the supply of oxygen is limited, H2S reacts with oxygen to form
a)
b)
c)
d)

81) If cold barium nitrite is mixed with H2SO4, which of the following products is correct ?
a)
b)
c)
d)

82) RRR Hypo is used in photography because of its
a) Reducing behaviour
b) Oxidising behaviour
c) Complex forming behaviour
d) Reaction with light

83) @ When hypo is treated with iodine, the ion formed is
a) Sulphate ion
b) Thionate ion
c) Tetrathionate ion
d) Sulphide ion

84) Sodium thiosulphate is prepared by
a)
b)
c)
d)

85) @ Hydrolysis of one mole of peroxodisulphuric acid produces
a) 2 moles of sulphuric acid
b) 2 moles of peroxomonosulphuric acid
c) 1 mole of sulphuric acid and 1 mole of peroxo monosulphuric acid.
d) 1 mole of sulphuric acid,1 mole of peroxysulphuric acid and 1 mole of hydrogen peroxide.

86) Na2CO3 reacts with SO2 in alkaline solution to give
a)
b)
c)
d)

87) Which one has the highest catenation power ?
a) S
b) Se
c) Te
d) Po

88) Which one of the following is called sulphuric anhydride ?
a)
b)
c)
d)

89) Which one of the following compounds has sp2-hybridisation ?
a)
b)
c)
d) CO

90) Which of the following does not produce a metallic sulphide on reaction with H2S ?
a)
b)
c)
d)

91) By passing H2S gas through acidified KMnO4 solution, we get
a)
b) S
c)
d)

92) Which of the following hydrides has the lowest boiling point ?
a)
b)
c)
d)

93) The molecular formula of sulphur is
a)
b)
c)
d)

94) The oxidation state of S in Na2S4O6 is
a) 2/3
b) 3/2
c) 3/5
d) 5/2

95) Which type of bond is there in H2S molecule ?
a) Ionic
b) Covalent
c) Coordinate
d) All of these.

96) Oxalic acid when heated with conc. H2SO4 gives
a)
b)
c)
d)

97) The oxidation numbers of sulphur in S8,S2F2, and H2S respectively are
a) 0,+1 and –2
b) +2,+1 and –2
c) 0,+1 and +2
d) +2,+1 and –2

98) The geometry of H2S and its dipole moment are
a) Angular and non zero
b) Angular and zero
c) Linear and nonzero
d) Linear and zero

99) When copper turnings are heated with conc. H2SO4 they give
a)
b)
c)
d)

100) In the preparation of H2SO4,V2O5 is used to catalyse which reaction?
a)
b)
c)
d)


Answer

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