P – BLOCK ELEMENTS – 11

1) The compound containing a coordinate bond is
a)
b)
c)
d) All

2) The normality of 2.3 M H2SO4 solution is
a) 2.3 N
b) 4.6 N
c) 0.46 N
d) 0.23 N

3) When potassium ferrocyanide crystals are heated with conc. H2SO4, the gas evolved is
a)
b)
c)
d) CO

4) Which of the following has a bond angle very close to 90°?
a)
b)
c)
d)

5) Which statement about H2S is false ?
a) It is a covalent compound
b) It is a gas with bad smell.
c) It is a weak base in water
d)

6) Ksp for HgS,Ag2S and PbS are 10-31,10-45 and 10-50 respectively. The solubilities are in the order
a)
b)
c)
d)

7) Na2S2O3 can be prepared by
a)
b)
c) Heating NaOH and S
d)

8) The shape of the molecule SF3Cl3 is
a) Trigonal bipyramidal
b) Cubic
c) Octahedral
d) Tetrahedral

9) Sulphur heptoxide is an anhydride of
a)
b)
c)
d)

10) SO2 acts as a/an
a) Bleaching agent
b) Oxidising agent
c) Disinfectant
d) All the above

11) H2S exhibits the following behaviour:
a) Basic nature
b) Acidic nature
c) Reducing nature
d) Both b and c

12) In which of the following molecules is sp2 hybridization involved ?
a)
b)
c) CO
d) Both a and b

13) The catalyst used in the manufacture of H2SO4 by the contact process is
a) Platinised asbestos
b)
c)
d) All are correct

14) Which of the following will give a black precipitate when H2S is passed through their acidic solution ?
a) Copper acetate
b) Lead acetate
c) Cobalt chloride
d) Both a and b

15) Which metal does not react with H2SO4 ?
a) Fe
b) Au
c) Pt
d) Both b and c

16) Mark the correct statements in the following: In diborane (B2H6)
a)
b) There is tetrahedral environment around each B atom
c) H-B-H bond angle is 122 degrees
d) All the above

17) Which of the following elements is the most electropositive ?
a) Al
b) B
c) Ga
d) In

18) Which of the following elements have IE values lying within the range of 550 to 600 KJ mol-1?
a) Al
b) Ga
c) ln
d) All the above

19) Boron does not form B3+ ions whereas Al forms AI3+ ions. This is because
a) The size of B atom is smaller than that of Al
b)
c)
d) Both (a) and (b)

20) Boron halides behave as Lewis acids because they
a) Are covalent compounds
b) Are ionic compounds
c) Have only six electrons in the valence shell
d) Have a lone pair of electrons on the B atom

21) The compound that is not a Lewis acid is
a)
b)
c)
d)

22) The order of the increasing acidic strength of is
a)
b)
c)
d)

23) Aluminium chloride acts as a strong Lewis acid because
a)
b)
c)
d)

24) Which of the following is a covalent compound ?
a)
b)
c)
d)

25) Aluminium chloride exists as a
a) Monomer
b) Dimer
c) Trimer
d) Polymer

26) Anhydrous AICI3 fumes in air because of
a) Dehydration
b) Hydration
c) Hydrolysis
d) Reduction

27) Which of the following hydroxides is acidic ?
a)
b)
c)
d)

28) The hydroxide of which of the following elements is amphoteric ?
a)
b)
c)
d)

29) Which of the following oxides is strongly basic ?
a)
b)
c)
d)

30) Which of the following metals is protected by a layer of its own oxide ?
a) Aluminium
b) Iron
c) Silver
d) Gold

31) If a molecule of MX3 has zero dipole moment, the sigma bonding orbitals used by M (atomic number < 21) are
a) Pure p
b) sp-Hybrid
c)
d)

32) Which of the following does not react with aqueous NaOH ?
a) B
b) Al
c) Ga
d) Tl

33) Which of the following does not react with water ?
a) Al
b) Na
c) Tl
d) B

34) Which of the following elements dissolves in NaOH to evolve H2 gas ?
a) Thallium
b) Indium
c) Aluminium
d) Magnesium

35) Which of the following statements is incorrect about aluminium ?
a)
b)
c)
d)

36) The three sets of elements are given below :

(/) Boron, aluminium, gallium, beryllium

(//) Boron, aluminium, gallium, indium

(III) Boron, aluminium, thallium, rubidium

Which of the above set/s contains an element which does not belong to group 13 and yet its

properties are quite similar to one of the group 13 elements?
a) (ii)
b) (iii)
c) (i)
d) (i) and (iii)

37) Which of the following hydrides is electron deficient?
a) NaH
b)
c)
d)

38) Which of the following statements is not true?
a) Al is ionic in all its compounds
b) Al is a light metal of great tensile strength
c) Al is a powerful reducing agent
d) Al does not react with steam even at high temperature

39) Which of the following statements is false ?
a)
b)
c) The boron hydrides are readily hydrotysed
d)

40) In B2H6
a) There is a boron-boron bond
b)
c) The boron atoms are linked through hydrogen bridges
d) All the atoms lie in the same plane

41) The reaction between LiH and AICI3 gives
a) Li
b)
c)
d)

42) The product x in the reaction, 6 LiH + 8 BF3 6 LiBF4 + x is
a)
b)
c)
d)

43) The compound which is commonly known as inorganic benzene is
a)
b)
c)
d)

44) Mark the wrong statement regarding BF3
a) It acts as a Lewis acid
b)
c) It is a volatile liquid at room temperature
d) It combines with ether to form boron tri-fluoride etherate

45) The + 3 oxidation state is more characteristic of
a) B
b) Al
c) Ga
d) All the above

46) The hardest substance amongst the following is
a)
b) Graphite
c)
d) SiC

47) Which of the following carbides on treatment with water evolves methane ?
a)
b)
c)
d) SIC

48) Which of the following pairs of elements shows a diagonal relationship ?
a) Li and Mg
b) Be and Al
c) B and Si
d) All of them

49) Aluminium oxide is not used as a
a) Dehydrating agent
b) Refractory material
c) Constituent of baking powder
d) Stationary phase in column chromatography

50) Which of the following reactions forms the basis of Goldschmidt aluminothermite process ?
a)
b)
c)
d)

51) Which of the following reactions does not take place?
a)
b)
c)
d)

52) Which of the following methods cannot be used for the preparation of anhydrous aluminium chloride?
a)
b) Heating a mixture of alumina and coke in a current of dry chlorine
c) Passing dry HCI gas over healed aluminium powder
d) Passing dry chlorine over heated aluminium.

53) The thermite process involves the use of
a)
b)
c)
d)

54) When strongly heated, orthoboric acid gives
a)
b)
c)
d) B

55) @ When borax is heated strongly it gives
a)
b)
c)
d)

56) The borax bead test is given by
a) All divalent metals
b) All heavy metals
c) All light metals
d) Metals which form coloured metaborates

57) Which of the following does not give the borax bead test?
a)
b)
c)
d)

58) When a nickel salt is heated with boric anhydride, a brown coloured bead is formed which is due to the formation of
a)
b) NiO
c)
d) None of the above

59) Alumina is insoluble in water because
a) It is a covalent compound
b) It has high lattice energy and low heat of hydration
c) It has low lattice energy and high heat of hydration
d)

60) Aqueous NaOH cannot be used as a precipitating reagent for converting AI3+ ions as Al (OH)3 because
a) NaOH is a weak base
b) NaOH is non-ionizable
c)
d)

61) The bonds present in borazole (B3N3H6) are
a)
b)
c)
d)

62) Which of the following compounds gives Cl2 above 40°C ?
a)
b)
c)
d) None of these

63) Which of the following sublimes on heating ?
a)
b)
c)
d)

64) Which of the following atomic numbers represents group 13 elements ?
a) 13
b) 31
c) 81
d) All the above

65) Which one of the following is a gas ?
a)
b)
c)
d) All the above

66) In which of the following elements does the inner electronic configuration contain 10 d-electrons?
a) B,Al
b) Ga, In
c) Al.Ga
d) None of these

67) Which one of the following is most abundant in the earths crust ?
a) AI
b) B
c) In
d) Ga

68) Alumina may be converted into anhydrous AICI3 by
a) Heating it with conc. HCI
b) Heating it in a current of dry chlorine
c) Heating it with rock salt
d) Mixing it with carbon and heating the mixture in a current of dry chlorine

69) Which of the statements about anhydrous AICI3 is correct ?
a)
b) It is not easily hydrolysed
c)
d) It is a strong Lewis base

70) Which of the following exhibits an inert pair effect ?
a) B
b) AI
c) Tl
d) SC

71) Which one is a covalent compound?
a)
b)
c)
d)

72) Thermite is a mixture of
a)
b)
c)
d)

73) In the aluminothermite process, Al acts as a/an
a) Flux
b) Oxidising agent
c) Reducing agent
d) Solder

74) Hydrogen will not reduce
a) Heated cupric oxide
b) Heated ferric oxide
c) Heated stannic oxide
d) Heated aluminium oxide

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

76) Which of the following statements is false ?
a) Boron trifluride is a strong Lewis base
b) Aluminium is a good reducing agent
c) Boron resembles in many properties with silicon
d)

77) On heating with carbon which of the following elements do not form carbides ?
a) B
b) Al
c) In, Ga
d) None of these

78) Borax is not used
a) As a styptic to stop bleeding
b) In making enamel and pottery glazes
c) As a flux in soldering
d) In making optical glasses

79) Which one of the following has the lowest melting point ?
a) B
b) Al
c) Ga
d) TI

80) Thallium shows different oxidation states because
a) It is a transition element
b) Of the inert pair effect
c) Of its amphoteric character
d) Of its higher reactivity

81) Which of the following minerals does not contain Al ?
a) Cryolite
b) Mica
c) Feldspar
d) Fluorspar

82) Which of the following processes does not involve a catalyst ?
a)
b) Thermite Process
c) Ostwald Process
d) Contact Process

83) Boron compounds behave as Lewis acids because of their
a) Acidic nature
b) Covalent nature
c) Electron deficient character
d) lonization property

84) The basic oxides among the following are
a)
b)
c)
d) b and c

85) Which one of the following is the strongest Lewis acid?
a)
b)
c)
d)

86) Boric acid is polymeric due to
a) Its acidic nature
b) The presence of hydrogen bonds
c) Its monobasic nature
d) Its geometry

87) The first ionization enthalpies (kJ/mol) for Li, Be, B and C have one of the following values. Which of these values corresponds to that of boron ?
a) 520
b) 800
c) 899
d) 1086

88) The inert pair effect plays an important role in the case of
a) F
b) Al
c) Si
d) TI

89) Which member of group 13 does not exhibit the group valency in its compounds ?
a) Boron
b) Aluminium
c) Gallium
d) Thallium

90) In which of the following elements is the + 1 oxidation state more stable than + 3?
a) B
b) Al
c) Ga
d) TI

91) Aluminium becomes passive in
a)
b)
c)
d) All

92) Which is true for an element R present in group 13 of the periodic table ?
a) It is a gas at room temperature
b) It has oxidation state of + 4
c)
d)

93) On the addition of mineral acid to an aqueous solution of borax, the following compound is formed:
a) Boron hydride
b) Orthoboric acid
c) Metaboric acid
d) Pyroboric acid

94) Which of the following is used in high temperature thermometry ?
a) Na
b) Ga
c) TI
d) Hg

95) Al is more reactive than Fe but Al is less easily corroded than Fe because
a) It is a noble metal
b) Oxygen forms a protective oxide layer on the surface of Al
c) Iron undergoes reaction easily with water
d) Fe form mono and divalent ions

96) Aluminium vessels should not be washed with materials containing washing soda since
a) Washing soda is expensive
b) Washing soda is easily decomposed
c) Washing soda reacts with Al to form insoluble aluminium oxide
d) Washing soda reacts with Al to form soluble aluminate

97) In the thermite welding process we use
a) Al powder
b) Fe powder
c) Ca powder
d) Al + Fe mixture

98) Which one of the following is a correct statement ?
a) Al is more acidic than B
b) B is basic while Al is amphoteric
c) B is acidic while Al is amphoteric
d) B and Al are amphoteric

99) Which one is metaboric acid ?
a)
b)
c)
d)

100) BCI3 is a planar molecule because in this molecule boron is
a)
b)
c) sp -Hybridized
d)


Answer

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