P – BLOCK ELEMENTS MCQs – 3

1) Nitrogen is a relatively inactive element because
a) Its atom has a stable electronic configuration
b) It has a low atomic radius
c) Its electronegativity is fairly high
d) The dissociation energy of its molecule is fairly high

2) Which one of the following substances is used in the laboratory for a fast drying of neutral gases?
a)
b) Active charcoal
c)
d)

3) When ammonia is passed over heated CuO, it is oxidised to
a)
b)
c)
d)

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

5) The ozone molecule is
a) Paramagnetic
b) Linear
c) Diamagnetic
d) Can be represented by a single structure

6) Pure nitrogen can be prepared from
a)
b)
c)
d)

7) Ozone belongs to which group of the periodic table?
a) 14
b) 15
c) 16
d) None of the above

8) Nitrogen gas is absorbed by
a) Aluminium carbide
b) Calcium carbide
c) Ferrous sulphate
d) Calcium hydroxide

9) Hydrogen at room temperature contains
a) 25% Ortho + 75% para
b) 25% Para + 75% ortho
c) 50% Ortho + 50% para
d) 66% Ortho + 34% para

10) Among the following oxides, the one which is most basic is
a) Zinc oxide
b) Magnesium oxide
c) Aluminium oxide
d) Nitrogen pentoxide

11) Which of the following substances will react with nitrogen when hot ?
a) Phosphorus
b) Lime water
c) Calcium chloride
d) Magnesium

12) Which of the following is a true peroxide?
a)
b)
c)
d)

13) Which of the following is/are amphoteric: BeO, SnO2 ?
a) BeO only
b)
c) Both
d) Neither

14) The gas used for sterilising water is
a)
b)
c)
d)

15) The process used to manufacture nitric acid is the
a) Solvay process
b) Ostwald process
c) Hall process
d) Haber process

16) NH3 has a much higher b.p. than PH3 because
a)
b)
c)
d)

17) There is no O – O bond in
a)
b)
c)
d)

18) The oxide insoluble in water is
a)
b)
c)
d)

19) About 20 km above the earth there is an ozone layer. Which one of the following statements about ozone and the ozone layer is true
a) The o\zone layer is beneficial to us because ozone cuts out the ultraviolet radiation of the sun
b) The conversion of ozone to oxygen is an endothermic reaction
c) Ozone has a triatomic linear molecule
d) The ozone layer is harmful to us because it cuts out radiation useful for photosynthesis

20) When SO2 gas is passed through cupric chloride solution
a) The solution becomes colourless, but no precipitate is formed
b) A white precipitate is formed, but no colour change.
c) No change takes place
d) the solution becomes colourless and a white precipitate is formed

21) Which of the following statements about white phosphorus are not true ?
a) It phosphoresces in air
b) It burns when heated in air
c)
d) It can be stored in contact with air

22) Which statement is correct?
a) Ozone is a resonance hybrid of oxygen
b) Ozone is an allotropic modification of oxygen
c) Ozone is an isomer of oxygen
d) Ozone has no relationship with oxygen

23) The oxide which cannot act as a reducing agent is
a)
b)
c)
d)

24) Iron when treated with conc. nitric acid
a) Readily reacts
b) Slowly reacts
c) Becomes passive
d) Gives ferrous nitrate

25) What is formed when HNO3 is heated?
a)
b)
c)
d) NO

26) NH3 and H2O form NH4+and OHby
a) Electrovalent bond
b) Covalent bond
c) Coordinate bond
d) None of these

27) Ammonia is bubbled through copper sulphate solution, and a deep blue solution results. The deep blue colour is due to formation of
a)
b)
c)
d) None of these

28) KO2 + CO2 ?(gas)
a)
b)
c)
d) CO

29) The test of O3 can be done by
a) Ag
b) Hg
c) Au
d) None of these

30) Of the following substances the one which does not contain oxygen is
a) Epsom salt
b) Bauxite
c) Cryolite
d) Dolomite

31) When HNO3 is heated with copper, the colour of the gas produced is yellowish-brown. The gas is
a)
b)
c) NO
d)

32) H2SO4 is very corrosive on skin. The primary reason is
a) It reacts with proteins
b) It acts as oxidising agent
c) It acts as a dehydrating agent and the absorption of water is highly exothermic
d) None

33) An element (X) forms compounds of the formula XCI3, and but does not form XCI5.Which of the following is the element X ?
a) B
b) Al
c) N
d) P

34) Which of the following is obtained when N2 reacts with calcium carbide?
a) Calcium cyanate
b) Calcium acetate
c) Calcium cyanamide
d) Calcium carbonate

35) Which of the following oxides reacts with HCI and NaOH ?
a) CaO
b) ZnO
c)
d)

36) Ozone reacts with moist iodine to form
a)
b)
c)
d)

37) Which one of the following pairs of substances will not evolve H2 gas on reaction?
a)
b) Iron and steam
c) Copper and HCI (aq)
d) Sodium and ethanol

38) Carbogen is a
a) Pure form of carbon
b)
c)
d)

39) @ Ozone is prepared by passing an electric discharge through oxygen. In this reaction
a) Energy is given out
b) Energy is absorbed
c) Oxygen is isomerized
d) Oxygen is dissociated into atoms

40) When KBr is treated with conc. H2SO4, reddish brown gas is evolved. The gas is
a)
b)
c)
d) None

41) Which is not the property of nitrogen?
a) Hydrogen Bonding
b) Catenation
c) Supporter of life
d) Low boiling point

42) Which oxide of nitrogen has nitrogen in the lowest oxidation state?
a) Nitric oxide
b) Nitrous oxide
c) Nitrogen dioxide
d) Dinitrogen tetroxide

43) If HNO3 changes into N2O, the oxidation number of N is changed by
a) 2
b) 6
c) 0
d) 4

44) Which of the following is formed by the action of water on sodium peroxide?
a)
b)
c)
d)

45) In the reaction HNO3 + P4O10 4 HPO3 + X, the product X is
a)
b)
c)
d)

46) Nitrogen atom has an atomic number of 7 and oxygen has an atomic number 8. The total number of electrons in a nitrate ion will be
a) 8
b) 16
c) 32
d) 64

47) The crystals of FeSO4 on heating gives
a)
b)
c)
d)

48) The conjugate acid of is
a)
b)
c)
d)

49) The relationship between the dissociation energy of N2 and that of N2+ is
a)
b)
c)
d)

50) On heating sodium metal in a current of dry ammonia, the compound formed is
a) Sodium amide
b) Sodium azide
c) Sodium nitride
d) Sodium hydride

51) The nitride ion in lithium nitride is composed of
a) 7 Protons + 10 electrons
b) 10 Protons + 10 electrons
c) 7 Protons + 7 electrons
d) 10 Protons + 7 electrons

52) The correct order of acidic strength is
a)
b)
c)
d)

53) The hybridization in the atomic orbitals of nitrogen in , and are
a)
b)
c)
d)

54) Ammonia can be dried by
a)
b)
c) CaO
d)

55) A deep brown gas is formed by mixing two colourless gases which are
a)
b)
c)
d)

56) Mark the oxide which is amphoteric in character:
a)
b)
c)
d) CaO

57) A metal which does not liberate H2 (g) from acids is
a) Cu
b) Fe
c) Mn
d) Zn

58) Which of the following has an odd number of electrons?
a) NO
b) CO
c)
d)

59) The bond angle in SO2 is nearly
a)
b)
c)
d)

60) The most abundant element in the earths crust (by weight) is
a) Si
b) Al
c) O
d) Fe

61) O3 is used to purify water since it
a) Is paramagnetic
b) Absorbs harmful UV radiations
c) Is reducing
d) Destroys bacteria and viruses

62) Gold is insoluble in nitric acid but dissolves in aqua regia. The enhanced solubility of gold arises from the
a)
b)
c)
d) Gold nitrate formation

63) Liquid ammonia and liquor ammonia are
a) The same
b) Different
c) Allotropes
d) None

64) Hydrazine reduces Fehling solution to
a) CuO
b)
c)
d)

65) A gas which was formerly used as an anaesthetic in dental surgery is
a) NO
b)
c)
d) All the above

66) Hydrogen has three isotopes. The radioactive isotope has the mass number
a) 3
b) 6
c) 2
d) All the above

67) Semi water gas is a mixture of
a)
b)
c)
d) None

68) An odd electron bond is not present in
a) NO
b)
c)
d) None of the above

69) Liquid oxygen is
a) Colourless
b) Pale yellow
c) Pale blue
d) Dark blue

70) Which of the following combines with Fe(II) ions to form a brown complex?
a)
b) NO
c)
d)

71) Which of the following colours is not associated with ozone?
a) Pale Blue
b) Blue
c) Purple
d) Green

72) Nitrogen can be purified from the impurities of oxides of nitrogen and ammonia by passing through
a) Ammoniacal copper sulphate
b) Conc. HCl
c) A solution of KOH
d) None

73) Hydrogen can form bonds
a) By losing an electron only
b) By gaining an electron only
c) By sharing an electron only
d) All the above

74) Hydrogen can be obtained from water
a) Only by electrolysis
b) Only by the action with active metals
c) Only by the reaction with metal hydrides
d) All the above

75) Which of the following on reaction with H2SO4, will not liberate hydrogen: Zn, Al2O3, Cu?
a)
b)
c)
d) Both Al2O3 and Cu

76) Oxygen is not evolved when
a) Potassium chlorate is heated
b) Sodium peroxide reacts with water
c) Ammonium nitrate is heated
d) All the above

77) Out of MgO, BeO, SnO, which is/are amphoteric ?
a) MgO and SnO
b) BeO and MgO
c) BeO and SnO
d) SnO alone

78) Which of the following statements are correct?
a)
b)
c)
d) All the above

79) Which of the following metals Fe, Al and Ni become passive on reacting with conc. HNO3?
a) Fe alone
b) Al and Fe
c) Ni and Al
d) All the three

80) sp2-Hybridization is found in the structures of
a)
b)
c)
d) both a and c

81) Which of the following is isoelectronic as well as having the same structure as that of N2O?
a)
b)
c)
d)

82) The molecule which has a pyramidal shape is
a)
b)
c)
d)

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

84) Orthophosphoric acid is
a) Monobasic
b) Dibasic
c) Tribasic
d) Tetrabasic

85) The number of P-O-P bonds in a cyclic metaphosphoric acid is
a) Zero
b) Two
c) Three
d) Four

86) The hybridisation of the atomic orbitals of nitrogen in NO, NO, and NH are
a)
b)
c)
d)

87) Which of the following forms of phosphorus is the most reactive?
a) Red phosphorus
b) Yellow or white phosphorus
c) Scarlet phosphorus
d) Violet phosphorus

88) Nitrogen can be obtained from air by removing
a) Oxygen
b) Hydrogen
c) Carbondioxide
d) Oxygen, CO2 , and noble gases

89) Repeated use of which of the following fertilizers would increase the acidity of the soil?
a) Urea
b) Potassium nitrate
c) Ammonium sulphate
d) Super phosphate of lime

90) An element (X) forms compounds of the formula XCl3,X2O5 and Ca3X2, but does not form XCl5. Which of the following is the element?
a) B
b) Al
c) N
d) P

91) There is very little difference in acid strengths in the series H3PO4, H3PO3 and H3PO2 because
a) Phosphorus is not a highly electronegative element
b) The hydrogens in these acids are not all bonded to phosphorus
c) Phosphorus in these acids exists in different oxidation states
d) Phosphorus oxides are less basic

92) Sodium pyrophosphate is
a)
b)
c)
d)

93) In the nitrogen family the H-M-H bond angle in the hydrides MH3 gradually becomes closer to 90° on going from N to Sb. This shows that gradually
a) The basic strength of the hydrides increases
b) Almost pure p-orbitals are used for M-H bonding
c) The bond energies of the M-H bond increases
d) The bond pairs of electrons becomes nearer to the central atom

94) Which oxide of nitrogen is a coloured gas?
a)
b) NO
c)
d)

95) Which of the following is a tetrabasic acid?
a) Orthophosphoric acid
b) Hydrophosphoric acid
c) Metaphosphoric acid
d) Pyrophosphoric acid

96) The basic character of the hydrides of VA (15) group elements decreases in the order
a)
b)
c)
d)

97) Among the trihalides of nitrogen which one is most basic?
a)
b)
c)
d)

98) Which of the following species has the highest dipole moment?
a)
b)
c)
d)

99) Group 15 of the periodic table consists of N, P, As, Sb and Bi. On passing from N to Bi, the oxides of the elements with the general formula M2O3 becomes
a) Stronger reducing agents
b) More ionic
c) More basic
d) More volatile

100) Which one of the following penta fluorides cannot be formed?
a)
b)
c)
d)


Answer :

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