P – BLOCK ELEMENTS – 18

1) Which of the following does not show allotropy ?
a) N
b) P
c) Bi
d) As

2) The molecule NO is described as
a) Odd-electron molecule
b) paramagnetic
c) very reactive
d) All the above

3) NO2 is a/an
a)
b)
c)
d)

4) In the reduction of HNO3 to N2O, the number of moles of electrons involved per mole of HNO3 is
a) 8
b) 4
c) 3
d) 6

5) The non combustible hydride is
a)
b)
c)
d)

6) RRR Which of the following does not undergo hydrolysis ?
a)
b)
c)
d)

7) The anhydride of nitric acid is
a) NO
b)
c)
d)

8) Which of the following oxides is neutral ?
a)
b)
c)
d)

9) Which of the following hydrides of nitrogen is acidic ?
a)
b)
c)
d)

10) Which of the following oxides may form a dimer ?
a)
b)
c)
d)

11) RRR Laughing gas is
a) Nitrous oxide
b) Nitric oxide
c) Nitrogen trioxide
d) Nitrogen pentoxide

12) The most basic and most stable hydride is
a)
b)
c)
d)

13) NH3 gas gives a brown ppt. with
a)
b)
c)
d)

14) Which hydride of group VA elements has the smallest bond angle ?
a)
b)
c)
d)

15) @ Laughing gas is prepared by heating
a)
b)
c)
d)

16) Which of the following has the lowest boiling point ?
a) Nitrogen
b) Phosphorus
c) Antimony
d) Arsenic

17) PCl5 exists but NCl5 does not because
a) Nitrogen has no vacant d-orbitals
b)
c) Nitrogen atom is much smaller
d) Nitrogen is inert

18) RRR The density of nitrogen gas prepared from air is slightly greater than that of nitrogen prepared by chemical reaction from a compound of nitrogen because atmospheric nitrogen contains.
a)
b) Argon
c)
d)

19) Which of the following molecules shows p-p bonding ?
a)
b)
c)
d)

20) Which is the anhydride of HNO2 ?
a)
b)
c)
d)

21) Which is not correct for N2O?
a) It is laughing gas
b) It is nitrous oxide
c) It is not a linear molecule
d) It is least reactive of all the oxides of nitrogen

22) Which of the following is most acidic ?
a)
b)
c)
d)

23) Which of the following statements are not true for phosphorus ?
a) It is a non-metal
b) It exists as a tetrahedral molecular solid
c) It is less reactive than nitrogen
d) the P-P bond is much weaker than the N – N bond

24) The chemical used for cooling in refrigeration is
a)
b)
c)
d)

25) In the manufacture of safety matches, we use
a) White P
b) Black P
c) Violet P
d) Red P

26) White phosphorus when boiled with a strong solution of NaOH produces
a) Phosphine
b) Posh acid
c) Phosphorous acid
d) No reaction

27) In the modern process phosphorus is manufactured by
a) Heating a mixture of phosphorite mineral with sand and coke in an electric furnace
b) Heating calcium phosphate with coke
c) Heating bone ash with coke
d) Heating phosphate mineral with sand

28) Which of the following statement regarding the hydrides of V A group elements is not correct ?
a) The thermal stability of the hydrides decreases down the group
b) The basic character of the hydrides decreases down the group
c) They are ionic and have planar structures
d) The reducing nature increases down the group

29) Which of the following is basic in nature ?
a)
b)
c)
d)

30) White phosphorus contains
a)
b)
c)
d)

31) Which one of the following statements is not correct for nitrogen ?
a) It has a small size
b) It is a typical non metal
c) It does not readily react with oxygen
d) d-orbitals are available for bonding

32) The semi-conducting form of phosphorus is
a) White
b) Red
c) Black
d) None

33) Which of the following properties of white phosphorus are shared by red phosphorus ?
a) It phosphoresces in air
b)
c)
d) It burns when heated in air

34) The bond angle in the ammonium ion is equal to
a)
b)
c)
d)

35) Rain water sometimes contains NH4NO3 because lightening in the sky causes the air to react and produce oxides of nitrogen and
a)
b)
c)
d) Noble gases

36) The dipole moment is highest for
a)
b)
c)
d)

37) Which of the following metals is not rendered passive by conc. HNO3 ?
a) Fe
b) Al
c) Cr
d) V

38) Oxidation of metals by HNO3 does not depend on the
a) Nature of the metal
b)
c) Temperature
d) presence of a catalyst

39) Colloidal sulphur is obtained by the action of HNO3 on
a)
b) HgS
c)
d)

40) NH3 has a much higher boiling point than PH3 because
a)
b)
c)
d)

41) In the group NO2+, NO+, NO, NO, which species has the strongest bond and shortest bond distance?
a)
b)
c) NO
d)

42) Bismuth does not form a stable pentahalide due to its
a) High electronegativity
b) Inert pair effect
c) Small size
d) Absence of d-orbitals

43) Which among the following is least basic ?
a)
b)
c)
d)

44) The oxidation state of +1 for phosphorus is found in
a)
b)
c)
d)

45) Phosphine is prepared by the reaction of
a)
b) P and NaOH
c)
d)

46) Which oxide of nitrogen is used as the catalyst in the lead chamber process for the manufacture of H2SO4 ?
a)
b)
c)
d)

47) Which of the following applies to hydrazoic acid?
a) Forms salts with bases
b) Is a reducing agent
c)
d) All are correct

48) Which halide does not exist?
a)
b)
c)
d)

49) Ammonia bottles should be opened after cooling for some time. This is because
a) It causes tears
b) It has a high vapour pressure
c) It is an explosive liquid
d) None

50) Which of the following is least malleable and ductile ?
a) Au
b) Ag
c) Ni
d) Bi

51) p – p multiple bonds are readily formed in
a) Oxides of nitrogen
b) Oxides of P
c) Oxides of Ag
d) Oxides of Bi

52) The strongest acidic oxide is
a)
b)
c)
d)

53) Nitric acid on standing develops a brownish colour, which may be due to the presence of
a)
b)
c)
d)

54) A molecule with a three electron bond is
a)
b) NO
c)
d)

55) RRR Which of the following is used in smoke screens ?
a)
b) HCl
c)
d)

56) Some of the reasons of reacting NH3 with hydrogen chloride are given below. Pick out the incorrect one.
a)
b)
c)
d)

57) In the Birkland and Eyde process, the temperature of the electric arc is about
a)
b)
c)
d)

58) In H3PO3
a) Each hydrogen atom is attached to oxygen
b) Two hydrogen atoms are attached to oxygen atoms
c) One atom of H is attached to oxygen
d) None is attached

59) Nitrogen can be purified from impurities of oxides of nitrogen and ammonia by passing through
a)
b) Conc. HCl
c) A solution of KOH
d) Alkaline solution of pyrogallol

60) A solution containing NH4Cl and NaNO2 on boiling produces
a) Nitrogen peroxide
b) Ammonia
c) Nitrous oxide
d) Nitrogen

61) The stable halide of nitrogen is
a)
b)
c)
d)

62) What is common to NH3 and PH3?
a) Odour
b) Combustibility
c) Basic nature
d) None of these

63) Which element of V group gives the most basic compounds with hydrogen ?
a) N
b) Bi
c) As
d) P

64) The sulphate of a metal has the formula M2(SO4)3. The formula of its phosphate will be
a)
b)
c)
d)

65) Which of the following has the minimum activation energy ?
a) Black
b) White P
c) Red P
d) Yellow P

66) NO2 can be obtained by heating
a)
b)
c)
d)

67) A white turbidity is obtained when one of the following reacts with water:
a)
b)
c) NaCl
d)

68) From which of the following reactions is phosphine not obtained ?
a) White P + NaOH
b) Red P + NaOH
c) Yellow P + NaOH
d) All of these

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

70) The oxide of nitrogen which is soluble in alcohol is
a)
b)
c) NO
d) Nitrous oxide is soluble in alcohol.

71) RRR Nitrolim is
a)
b)
c)
d)

72) The colourless gas with a smell of rotten fish is
a)
b)
c)
d)

73) Calcium phosphide is used in smoke screens because it
a) Burns to form soot
b)
c) Immediately catches fire in air
d) Is a gas which brings tears to the eyes

74) Which of the following substances can be used to remove nitrogen from air ?
a) P
b) Mg
c)
d)

75) The bond order of NO is
a) 1.5
b) 2.0
c) 2.5
d) 3.0

76) When iron is brought in contact with conc. HNO3
a) It reacts immediately
b) It reacts very slowly
c) It becomes passive
d) It gives ferrous nitrate

77) Which of the following is the correct statement ?
a)
b) Nitric oxide is diamagnetic
c) Nitric oxide is an endothermic compound
d) Nitric oxide gas is used to induce general anaesthesia

78) In the action of HNO3 on metals, the evolution of NO2 is favoured by
a)
b)
c)
d)

79) The acid of phosphorus which coagulates albumin is
a)
b)
c)
d)

80) PH3 gas is
a) Acidic
b) Basic
c) Neutral
d) Amphoteric

81) Each of the following is true of white and red phosphorus except that they
a)
b) Can be oxidised by heating in air
c) Consist of the same kind of atoms
d) Can be converted into one another

82) Ammonium nitrite is not used for the laboratory preparation of nitrogen because it is
a) Very explosive
b) Explosive
c) Not easily available in the pure state
d) None

83) Which of the following reagents can separate nitric oxide from nitrous oxide ?
a) Sodium nitroprusside solution
b)
c)
d) Ammonical silver nitrate solution

84) Which of the following elements does not form stable diatomic molecules ?
a) Iodine
b) Phosphorus
c) Nitrogen
d) Oxygen

85) Pure nitrogen gas is obtained from
a)
b)
c)
d) None

86) Aqueous solution of ammonia contains
a)
b)
c)
d)

87) RRR Bones glow in dark. This is due to.
a) The presence of red phosphorous
b) Conversion of white P into red P
c) Slow combustion of white P in contact with air
d) Conversion of red P into white P

88) Which one of the following formulae does not represent a salt derived from phosphoric acid, H3PO4 ?
a)
b)
c)
d)

89) A compound which leaves behind no residue on heating is
a)
b)
c)
d) None of these

90) Which of the following when heated gives off a gas or a mixture of gases which cannot relight a glowing splinter ?
a)
b)
c)
d)

91) RRR The gas used in the manufacture of ice cream is
a)
b)
c) NO
d)

92) RRR Conc. HNO3 oxidises sugar to
a)
b)
c)
d) Oxalic acid and water

93) RRR Which phosphorus is in Phossy Jaw ?
a) White
b) Red
c) Scarlet
d) Violet

94) RRR Phosphorus present in the bones is in the form of
a) Calcium sulphate
b) Calcium phosphate
c)
d) Calcium fluoride

95) Which is correct about white phosphorus ?
a)
b) It is a violet red solid
c) It is not poisonous
d)

96) The gas not having oxidising and bleaching properties is
a) Chlorine
b) Ozone
c) Sulphur dioxide
d) Nitrous oxide

97) The heat of vapourisation of NH3 is due to
a) Its basic nature
b) Its polar nature
c) Hydrogen bonding
d) Solubility in water

98) The compound of phosphorus used as a drying and desiccating agent is
a)
b)
c)
d)

99) Nitric oxide has — valence electrons
a) 10
b) 13
c) 11
d) 12

100) The acid used in soft drinks is
a)
b)
c)
d)


Answer

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