P – Block Elements – 1

1) Ozone reacts with NO2 as per the equation
O3 + 2NO2O2+ N2O5
The mechanism of the reaction
O3+NO2NO3+O2(slow)
NO3+ NO2 N2O5(fast)
The rate law is
a) r=k[O3] [NO2]2
b) r=k[NO3] [NO2]
c) r=k[O3] [NO2]
d) r=k[O3] [NO2]1/2

2) 75% of the total constituents of earth consist of
a) Nitrogen and Oxygen
b) Silicon and Oxygen
c) Silicon and Nitrogen
d) Sulphur and Phosphorus

3) Synthesis gas is a mixture of
a) CO + H2
b) CO + N2
c) CO + CO2
d) CO2 + N2

4) A diatomic molecule containing an even number of electrons out of which two are unpaired is
a) H2
b) O2
c) N2
d) F2

5) A pair of amphoteric oxides
a) Na2O, MgO
b) AI2O3,MgO
c) SiO2,AI2O3
d) SiO2,MgO

6) The decreasing order of O-O bond length in O2,O3 and H2O2
a) O2 >O3 > H2O2
b) H2O2 > O3 > O2
c) H2O2 > O2 > O 3
d) O3 > O2> H2O2

7) Two compounds which on heating give N2 are
a) NH4NO2, NH4NO3
b) NH4NO2, (NH4)2 Cr2O7
c) NH4NO3, (NH4)2 Cr2O7
d) HNO3,NaN3

8) The number of moles of HNO3 required to react with 1 mole of phosphorus is
a) 10
b) 4
c) 6
d) 20

9) The drying agent for drying NH3 gas is
a) anhydrous CaCI2
b) conc H2SO4
c) quick lime
d) P2O5

10) An ion which can give an intense violet coloration with Fe(CN)5NO2- is
a) Na+
b) S2-
c) F
d) AI3+

11) The oxyacid/s of phosphorus which is/are reducing agents
a) HPO3
b) H3PO2
c) H3PO3
d) both (b) and (c)

12) A metal nitrate which does not give NO2 on heating is
a) LiNO3
b) Mg(NO3)2
c) Pb(NO3)2
d) KNO3

13) An oxide of nitrogen which is a supporter of combustion is
a) N2O
b) NO
c) NO2
d) N2O4

14) The type of overlapping in the multiple bond in POCI3 is
a) pp-pp
b) pp-dp
c) dp-dp
d) none of the above

15) The increasing order of bond angle in hydrides of group V is
a) Bi H3 < SbH3 < AsH3 < PH3 < NH3
b) BiH3 > SbH3 > AsH3 > PH3 > NH3
c) NH3 < BiH3 < SbH3 < AsH3 < PH3
d) NH3 < PH3 < AsH3 < SbH3 < BiH3

16) Which of the following has an N-O-N bond
a) N2O
b) N2O3
c) N2O4
d) N2O5

17) The strongest and the most powerful oxidising acids among the oxyacids of chlorine will be
a) HOCI, HCIO4
b) HCIO4, HOCI
c) HCIO4,HCIO4
d) HOCI, HOCI

18) What is the weight of oxygen required for the complete combustion of 2.8 kg of ethylene?
a) 2.8 Kg
b) 6.4 Kg
c) 9.6 Kg
d) 96 Kg

19) How many moles of KI are required to produce 0.4 moles of ?
a) 0.4
b) 0.8
c) 3.2
d) 1.6

20) The number of oxygen atoms in 4.4 g of is approximately
a)
b)
c)
d)

21) Boron has two stable isotopes, and . The atomic mass that should appear for boron in the periodic table is
a) 10.8
b) 10.2
c) 11.2
d) 10.0

22) The molecular weights of and are 32 and 64 respectively. At and 150 mm Hg pressure, one litre of contains molecules. The number of molecules in two litres of under the same conditions of temperature and pressure will be
a) N/2
b) N
c) 2N
d) 4N

23) The number of moles of oxygen in one litre of air containing 21% oxygen by volume, in standard conditions is
a) 0.186 mole
b) 0.21 mole
c) 2.10 mole
d) 0.0093 mole

24) The number of moles of in 13.5 g is
a) 0.1
b) 0.2
c) 0.3
d) 0.4

25) The number of atoms is greatest in
a) 71 g of chlorine
b) 48 g of magnesium
c) 4 g of hydrogen
d) All the above contain the same number of atoms

26) The reactivity of NO is due to
a) Its low molecular weight
b) Its gaseous state
c) its odd electron
d) None of the above

27) Nitrogen is an essential constituent of all
a) Proteins
b) Fats
c) Proteins and fats
d) None of these

28) Which among the following forms the most basic oxide?
a) Bi
b) N
c) As
d) P

29) Which phosphorus is used as rat poison?
a) White
b) Red
c) Scarlet
d) Violet

30) The basicities of the acids H3PO2,H3PO4 and H4P2O7 are respectively
a) 1, 2, 3, 7
b) 2, 3, 4, 7
c) 1, 2, 3, 4
d) 1, 2, 3, 5

31) Red phosphorus is less reactive than yellow phosphorus because
a) It is red in colour
b)
c) It is hard
d) It is highly polymerised

32) The gas obtained on heating ammonium nitrite is
a)
b)
c)
d)

33) Phosphorus trioxide on reaction with water yields
a) Phosphoric acid
b) Pyrophosphoric acid
c) Phosphorus acid
d) a mixture of phosphorus acid and pyrophosphoric acid

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

35) P4O10 reacts with water to give
a) Hypophosphorus acid
b) Orthophosphorus acid
c) Hypophosphoric acid
d) Orthophosphoric acid

36) Which of the following compounds are unstable?
a)
b)
c)
d) NO

37) Which is a basic oxide?
a)
b)
c)
d)

38) O2, N2 are present in the ratio of 1 : 4 by weight. The ratio of the number of molecules is
a) 4 : 1
b) 1 : 4
c) 2 : 1
d) 7 : 32

39) One of the acids given below is formed from P2O3 and the rest are formed from P2O5. The acid formed from P2O3 is
a)
b)
c)
d)

40) Which of the following is not correct?
a) White and red phosphorus react equally with chlorine at room temperature
b) White phosphorus is metastable, while red phosphorus is stable
c) White phosphorus is lighter than red phosphorus
d) White phosphorus is highly poisonous,while red phosphorus is not

41) PH4I reacts with NaOH to form
a)
b)
c)
d)

42) Solid PCl5 exists as
a)
b)
c)
d)

43) The N-H bond in NH3 is
a) Covalent
b) Ionic
c) Dative
d) Hydrogen

44) Ozone with Kl solution produces
a)
b)
c) HI
d)

45) Amongst the trihalides of nitrogen, which one is the least basic?
a)
b)
c)
d)

46) Oxygen was discovered by
a) Priestley
b) Boyle
c) Scheele
d) Cavendish

47) Which one of the following elements occurs free in nature?
a) Nitrogen
b) Phosphorus
c) Arsenic
d) Antimony

48) Which of the following compounds is not known?
a)
b)
c)
d)

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

50) FeSO4 forms a brown ring with
a)
b)
c) NO
d)

51) The most abundant element on earth is
a) O
b) S
c) Se
d) Te

52) Nascent hydrogen consists of
a) Hydrogen atoms with excess of energy
b) Hydrogen molecules with excess energy
c) Hydrogen ions in excited state
d) Solvated protons

53) Nitrogen (I) oxide is produced by the
a) Thermal decomposition of ammonium nitrate
b)
c) Thermal decomposition of ammonium nitrite
d) Interaction of hydroxyl amine and nitrous acid

54) Ammonia gas can be collected by the downward displacement of
a)
b) Brine
c) Water
d) Mercury

55) The oxide of nitrogen formed in the atmosphere during lightning is
a)
b)
c)
d)

56) A mixture of ammonia and air at about 800°C in the presence of Pt gauze forms
a)
b) NO
c)
d)

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

58) Ozone turns trimethyl paper
a) Green
b) Violet
c) Red
d) Black

59) The gases respectively absorbed by alkaline pyrogallol and oil of cinnamon is
a)
b)
c)
d)

60) The structure of NH3 is
a) Trigonal
b) Tetrahedral
c) Pyramidal
d) Trigonal bipyramidal

61) It is possible to obtain oxygen from air by fractional distillation because
a) Oxygen is in a different group of the periodic table from nitrogen
b) Oxygen is more reactive than nitrogen
c) Oxygen has a higher b.p. than nitrogen
d) Oxygen has a lower density than nitrogen

62) Oxygen does not react with
a) P
b) Na
c) S
d) Cl 2

63) Nitrogen dioxide
a) Dissolves in water forming nitric acid
b) Does not dissolve in water
c) Dissolves in water to form nitrous acid and gives off oxygen
d) Dissolves in water to form a mixture of nitrous and nitric acids

64) Which of the following does not liberate O2 in Bunsen burner ?
a) MgO
b)
c)
d)

65) Oxygen can be obtained from bleaching powder by
a) Adding dilute acid
b)
c) Heating with a cobalt salt
d) Adding alkalies

66) Nitric oxide may be prepared by the
a)
b)
c)
d) None of these

67) Ammonia water makes a good cleaning agent because it
a) Is weakly basic
b) Emulsifies grease
c) Leaves no residue when wiped off
d) All are true

68) The structure of phosphide ion is similar to that of a
a) ion
b) ion
c) Nitride ion
d) ion

69) 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 in eyes

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

71) One would expect a proton to have a very large
a) Charge
b) lonisation potential
c) Hydration energy
d) Radius

72) Which one of these is basic?
a)
b)
c)
d)

73) Which among the following is the most acidic?
a)
b)
c)
d)

74) The chemical inertness of is attributed to
a) the presence of a large number of bonding electrons in comparison to anti-bonding electrons
b) Its high heat of dissociation
c) the presence of a triple bond between nitrogen atoms which makes the molecule quite stable
d) All the statements are correct

75) In the preparation of oxygen from potassium chlorate, manganese dioxide acts as
a) A Promoter
b) An Activator
c) An Oxidising agent
d) A Catalyst

76) Which of the following is not an isotope of oxygen?
a)
b)
c)
d)

77) Dioxygen present in the atmosphere is believed to be produced by
a) Sun
b) Photosynthesis
c) Water
d) Air

78) Which gives off oxygen on moderate heating?
a) Cupric oxide
b) Mercuric oxide
c) Zinc oxide
d) Aluminium oxide

79) Ozone gives violet colour with
a) Litmus paper
b) Benzidine paper
c) Turmeric paper
d) Tetra ethyl base paper

80) The strongest oxidising agent is
a)
b)
c)
d)

81) Which of the following is not an acidic oxide ?
a)
b) CO
c)
d)

82) Basic oxides are formed by
a) Non metals
b) Transition metals in higher oxidation states
c) Amphoteric metals
d) Alkali metals

83) Which of the following is not a neutral oxide?
a)
b)
c) CO
d) NO

84) Pick out the incorrect statement regarding ozone
a)
b)
c)
d) It causes tailing of mercury

85) Ozone tails mercury. The reaction involves, with reference to mercury,
a) Reduction
b) Oxidation
c) Substitution
d) None of the above

86) The substance which does not liberate oxygen on treatment with ozone is
a) PbS
b)
c)
d) Hg

87) A mercury meniscus is regained by adding
a)
b)
c) Alcohol
d)

88) A large part of the harmful UV radiations of the sun does not reach the surface of the earth. This is because in the upper atmosphere, there is a layer of
a)
b)
c)
d) NO

89) Ozone is not readily soluble in
a) Turpentine oil
b)
c) Cinnamon oil
d) Water

90) Which of the following is not true of ozone ?
a) Turns benzidine paper brown
b) Turns tetramethyl base violet
c) Is tested by tailing of Hg
d) None. All of these are true

91) Moist iodine reacts with ozone to give
a) HI
b)
c)
d)

92) Ozone is
a) An oxidant, not a reductant
b) A reductant, not an oxidant
c) An oxidant as well as a reductant
d) An acid

93) Which one of the following properties is not correct for ozone?
a) It oxidises PbS
b) It oxidises HI
c) It oxidises Hg
d) It cannot act as a bleaching agent

94) Ammonia is produced when ammonium chloride is heated with
a) Potassium nitrate
b) Slaked lime
c) Calcium carbonate
d) Sodium nitrite

95) Ammonia reacts with excess chlorine to form
a)
b)
c)
d)

96) Nesslers reagent is an alkaline solution of
a)
b)
c)
d)

97) Nesslers reagent is used for the detection of
a)
b)
c)
d)

98) Ostwalds process for the manufacture of nitric acid involves
a)
b)
c)
d) Passage of steam over red hot coke

99) When zinc reacts with very dilute nitric acid, one of the products obtained is
a) NO
b)
c)
d)

100) Hydrogen may be liberated from nitric acid by the action of
a) Copper
b) Zinc
c) Magnesium
d) Mercury


Answer :

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