P – BLOCK ELEMENTS – 15

1) Which of the following statements is not correct?
a) Diborane has two three centred B-H-B bonds
b) Tetraborane has four three centred B-H-B bonds and one B-B bond
c) Diborane has one three centred B-H-B bond
d)

2) Which of the following statements regarding borax is correct ?
a) It is used in the manufacture of optical glass
b) It is widely used as a flux
c) It is used as a water softener
d) All are correct

3) Boric acid, H3BO3 has a
a) Trigonal structure
b) Tetrahedral structure
c)
d)

4) In the borax bead test, which component of the bead reacts with a basic radical to form metaborate?
a)
b)
c)
d)

5) Borazole is obtained by reacting B2H6 with NH3 in the ratio
a) 1:2
b) 2:1
c) 1:4
d) None

6) Which of the following statements is not correct ?
a) Pyrex glass is made of borosilicate glass
b) Borosilicate is obtained from boric acid
c) Boric acid is obtained by treating boric oxide and water
d) Boric oxide is obtained by treating diborane with water

7) The aluminium salt commonly used to stop bleeding is
a) Aluminum sulphate
b) Potash alum
c) Aluminium chloride
d) Aluminum fluoride

8) ln the electrolysis of alumina, a layer of powdered coke is spread on the surface of the electrolyte in the cell
a) To increase the electrical conductivity
b) To decrease the melting point of alumina
c) To prevent the loss of heat by radiation and burning of carbon electrode
d) None of the above

9) Which of the following statements is not correct for Al ?
a)
b)
c)
d)

10) The main impurities present in red and white bauxite are respectively
a)
b)
c)
d)

11) Aluminothermy used for the spot welding of large iron structures is based on the fact that
a) As compared to iron, Al has great affinity for oxygen
b) As compared to Al, Fe has greater affinity for oxygen
c) the reaction between iron and oxygen is endothermic
d) the reaction between Al and oxygen is endothermic

12) Alumina on heating with carbon in atmosphere of N2 gives
a) Al + CO
b)
c) AlN + CO
d)

13) The protective film of oxide on the surface of Al metal may be strengthened by
a) Galvanising
b) Cathodising
c) Sheradising
d) Anodising

14) Which reaction cannot give anhydrous AlCl3 ?
a)
b) Passing dry HCl over heated Al powder
c) Passing dry chlorine over heated Al powder
d)

15) The role of fluorspar (CaF2) which is added in small quantities in the electrolytic reduction of alumina in fused cryolite (Na3AlF6) is
a) As a catalyst
b) To make the fused mixture conducting
c) To increase the temperature of the melt
d) To decrease the rate of oxidation of carbon at the anode

16) In the electrolysis of alumina cryolite is added to
a) Lower the m.p. of alumina
b) To increase the electrical conductivity
c) both (a) and (b)
d) None

17) The dissolution of (Al(OH)3 in a solution of NaOH gives
a)
b)
c)
d)

18) Which of the following is pseudo-alum ?
a)
b)
c)
d) None

19) Electrolytic reduction of pure alumina is not possible because
a) It is a bad conductor of electricity
b) It melts at a very high temperature
c) Both
d) None

20) Boric acid is prepared from borax by the action of
a) HCl
b) NaOH
c) CO
d) NaCO

21) The product formed in the reaction, BCl3 + H2O à Products is
a)
b)
c)
d) No reaction

22) The composition of mica is
a)
b)
c)
d)

23) Which boron compound is optically active ?
a) Boron trifluoride
b) Boron anhydride
c) Boro salicylic acid
d) Sodium tetraborate

24) The percentage of lead in a lead pencil is
a) Zero
b) 20%
c) 80%
d) 70%

25) Which one of the following is not a transition metal?
a) Chromium
b) Titanium
c) Lead
d) Tungsten

26) Lead sulphate is soluble in
a)
b) Conc HCl
c) A solution of ammonium acetate
d) Water

27) Carborundum is
a) BN
b)
c) SiC
d)

28) Moderate electrical conductivity is shown by
a) Silica
b) Diamond
c) Graphite
d) Carborundum

29) In graphite, carbon is
a)
b)
c) sp-hybridised
d) Non-hybridised

30) Which of the following is a pseudo solid?
a) Diamond
b) Glass
c) Rock salt
d)

31) Carbon and silicon have
a) the same physical properties
b) Different physical properties
c) the same physical but different chemical properties
d) Different chemical and physical properties

32) Diamond is an example of a
a) Covalent solid
b) Electrovalent solid
c) Solid with hydrogen bonding
d) Glass

33) The structure and hybridisation of Si(CH3)4 is
a) Bent, sp
b)
c)
d)

34) Quartz is a crystalline variety of
a) Sodium silicate
b) Silicon carbide
c) Silicon
d) Silica

35) Which of the following shows the bond in silicon?
a)
b) Si – C – Si – O- Si
c) Si – C – Si – C – Si
d) Si – Si – Si – Si

36) Which is the largest stable atom?
a) V
b) Na
c) Al
d) Pb

37) A lead pencil contains
a) Pb
b) PbS
c) Graphite
d) FeS

38) CO2 is isostructural with
a)
b)
c)
d)

39) The ion that can be precipitated by HCI as well as H2S is
a)
b)
c)
d)

40) The molecular shapes of SF4, CF4 and XeF4 are.
a) The same, with 2, 0 and 1 lone pairs of electrons respectively
b) The same with 1, 1 and 1 lone pairs of electrons respectively
c) Different with 0, 1 and 2 lone pairs of electrons respectively
d) Different with 1, 0 and 2 lone pairs of electrons respectively

41) Carbon forms a large number of compounds because it has
a) a fixed valency
b) a non-metallic nature
c) a high ionisation potential
d) the property of catenation

42) In which of the following carbides is the carbon atom tetrahedrally hybridised?
a) SiC
b)
c)
d) All are correct

43) In which of the following carbides carbon atom is diagonally hybridised with 2p bonds and 2 bonds?
a)
b)
c)
d) All are correct

44) Which of the following is most ionic in character?
a)
b)
c)
d)

45) The compounds of which IV group element show the most pronounced inert pair effect?
a) C
b) Si
c) Ge
d) Sn

46) Carbon reacts with metals to form
a) Carbides
b) Carbonates
c) Hydroxides
d) Oxides

47) Which of the following carbides derives its structure by the accommodation of carbon atoms in a closely packed lattice of metal atoms?
a) TiC
b) UC
c) ZrC
d) All are correct

48) Which of the following statements is correct? With respect to the increase in atomic number of elements in the carbon family (Group 14),
a) Their metallic character decreases
b) The stability of + 2 oxidation state increases
c) Their ionisation energy increases
d) Their atomic size decreases

49) Water gas is a mixture of
a)
b)
c)
d)

50) Which of the following statement about IV group elements (C to Pb) is not correct?
a) The thermal stability of hydrides decreases from methane to lead tetrahydride
b) All form tetra fluorides, tetrachlorides, tetra bromides
c) Only Sn and Pb form dichlorides
d) All form tetra iodides

51) p p– d p bonding exists in.
a) Diamond
b) Graphite
c) Trisilylamines
d) None

52) Dry ice is
a) Solid ice without any water
b)
c)
d) Solid benzene

53) The most commonly used reducing agent to reduce Fe3+ to Fe2+, Hg2 to Hg+, I2 to I is
a)
b)
c)
d)

54) Which is not correct about carbon monoxide, CO?
a) Carbon in CO is sp hybridised and is linear molecule
b) CO is a ligand because it has a lone pair of electrons in the carbon atom
c) CO is the reducing agent in metallurgy of iron
d) CO has the structure C – O

55) Which among the following has the maximum tendency to exhibit a stable +2 oxidation state?
a) C
b) Ge
c) Pb
d) Si

56) The oxidising power of the tetravalent species of the following elements increases in the order
a) Ge< Pb< Sn
b) Ge < Sn < Pb
c) Pb < Ge < Sn
d) None

57) Which is not true about SiO2?
a) It is a network solid
b) It is attacked by molten NaOH
c) It is attacked by HF
d) It is the basic structural unit of diamond

58) Which of the following is an interstitial carbide?
a)
b)
c) ZrC
d) All the above

59) Which of these metals have atomic radii too small to permit the formation of interstitial carbides?
a)
b)
c)
d) All the above

60) The main constituent of water glass is
a) Sodium silicate
b) Magnesium silicate
c) Calcium silicate
d) Silicic acid

61) Flint glass is made from
a)
b)
c)
d) All are correct

62) Pyrex glass is
a)
b)
c)
d) Sodium borosilicate and aluminium borosilicate

63) PbCl4 exists but PbBr4 and PbI4 do not because of
a)
b) the bigger size of Br and I
c) the more electropositive nature of bromine and iodine
d) Chlorine being a gas

64) Sugar of lead is
a)
b)
c)
d)

65) C and Si belong to IV group. The maximum co-ordination number of carbon in commonly occurring compounds is 4, whereas that of silicon is 6. This is due to the
a) Large size of silicon
b) Availability of low lying d- orbitals in silicon
c) More electropositive nature of silicon
d)

66) Coke is obtained from coal by
a) Cracking
b) Fractional distillation
c) Destructive distillation
d) Fractionation

67) Which of the following is not correct in the case of carbon?
a) It exhibits catenation
b) It shows the inert pair effect
c) It forms compounds with multiple bonds
d) It has high ionisation energy

68) Litharge is chemically
a) PbO
b)
c)
d)

69) Chrome yellow is
a)
b)
c)
d)

70) SiCl4 is hydrolysed because
a)
b) Si can expand its co-ordination number beyond six
c)
d) Si is non-volatile

71) Silicates are formed by the replacement of positively charged Si4+ ions in SiO tetrahedra by
a)
b)
c)
d) All are correct

72) Silica readily dissolves in
a) HF
b) HCl
c) HI
d)

73) The tendency to form pp – pp multiple bonds
a) Is prominent for carbon
b) Is less prominent for Si
c) Is non-existent for Sn and Pb
d) All the above

74) The correct order of the size is
a) Be>C>F>Ne
b) Be<c<f<ne< font=””>
c) Be>C>F<ne< font=””>
d) F<na<ba<c< font=””>

75) Which one of the following statements is not correct?
a) Zn dissolves in NaOH solution
b) CO reduces Fe (III) oxide to Fe
c) Hg (II) iodide dissolves in excess KI solution
d) Tin IV chloride is made by dissolving Sn in conc. HCl

76) The use of graphite as a lubricant depends upon its
a) Black colour
b) Softness
c) Being a good conductor of electricity
d) None is correct

77) The inert pair effect is maximum in
a) Pb
b) Si
c) Ge
d) Sn

78) Which of the following glasses have the smallest coefficient of thermal expansion?
a) Soft glass
b) Sodalime glass
c) Safety glass
d) Pyrex glass

79) Tetrahalides of IV A group have the geometry
a) Square planar
b) Octahedral
c) Tetrahedral
d) Trigonal bipyramidal

80) The calorific value of producer gas is
a)
b)
c)
d) None

81) Which of the following is not a net-work solid?
a) Dry ice
b) Silica
c)
d)

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

83) A salt which gives CO2 with hot H2SO4 and also decolourises acidified KMnO4 on warming is
a)
b)
c) Oxalate
d) Acetate

84) An example of a covalent crystalline solid is
a) NaF
b) Silicon
c) Al
d) Ar

85) Hot and conc. HNO3 reacts with carbon to form
a)
b) CO
c)
d)

86) A form of carbon used for refractory lining is
a) Charcoal
b) Coke
c) Carbon black
d) Graphite

87) RRR Dry powder extinguishers contain
a) Sand
b)
c)
d) Sand and baking soda

88) Which of the following is not a characteristic property of carbon?
a) Catenation
b) Multiple bond formation
c) Availability of d orbitals for bonding
d) Highest electronegativity in the group

89) Silicon is an important constituent of
a) Chlorophyll
b) Haemoglobin
c) Rocks
d) Amalgams

90) Which of the following metals shows allotropy?
a) Sn
b) Ca
c) K
d) Pb

91) Carbon differs from other elements of the group. Which is the false statement?
a) Due to its limitation of co-ordination number 4
b) Due to d-orbitals in penultimate shell
c) Due to its unique ability to form long chains
d) Due to its marked tendency to form long chains (catenation)

92) Which of the following is the strongest bond?
a) Sn-Sn
b) Pb-Pb
c) Si-Si
d) C-C

93) The stability of the +2 oxidation state of Pb is due to the
a) Electronic configuration
b) Inert pair effect
c) Resonance
d)

94) A colourless gas which burns with a blue flame and reduces hot copper oxide to copper is
a) CO
b)
c)
d)

95) The reducing power of Ge2+, Sn2+ and Pb2+ decreases in the order
a)
b)
c)
d)

96) Massicot is prepared by
a)
b) Heating Litharge
c) Heating red lead
d) Heating lead nitrate

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

98) Graphite is used in nuclear reactors
a) As a fuel
b) As a lubricant
c) For lining the inside of the reactor as an insulator
d) For reducing the velocity of neutrons

99) In metal carbonyls of the general formula M(CO)X, where X = 4 and M = metal, the metal is bonded to
a) Carbon and oxygen
b) Carbon
c) Oxygen
d)

100) Dry ice is effective in seeding clouds because
a)
b) It increases water content of the cloud
c)
d) Upon sublimation, it lowers the temperature of water


Answer

 

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