P – BLOCK ELEMENTS – 14

1) The correct order of melting points of group 13 elements is
a) B > Al > Ga > In > TI
b) B < Al < Ga < In < Tl
c) B > Al < Tl > In > Ga
d) None

2) Aluminium is more reactive than iron but aluminium is less corroded than iron because
a) Al is a noble metal
b) Fe undergoes reaction easily with water
c) Oxygen forms a protective oxide layer
d)

3) Aluminium deposited as vapour on glass forms a good mirror, essentially because
a) It has a better shine than Ag.
b) It does not scratch
c) Coating is much smoother
d) It does not tarnish in air

4) Which of the following oxides is amphoteric?
a)
b)
c)
d)

5) Which of the following is not a Lewis acid ?
a)
b)
c)
d)

6) Which of the following is most basic?
a)
b)
c)
d)

7) When borax is heated with cobalt nitrate, a blue bead is formed. The bead consists of
a) Cobalt metaborate
b) Sodium metaborate + cobalt oxide
c)
d)

8) Inorganic graphite, BN
a) Has a graphite-like layer structure
b)
c) Is a white refractory solid
d) All of these

9) On the addition of mineral acid to an aqueous solution of borax, the following is formed:
a) Borodihydride
b) Orthoboric acid
c) Metabolic acid
d) Pyroboric acid

10) Inorganic benzene, B3N3H6 borazole,
a)
b) Is iso-electronic with benzene
c) Has a cyclic structure
d) All of these

11) Borax is
a) Sodium meta borate
b) Sodium borate
c) Sodium tetra borate
d) Sodium thioborate

12) Which of the following properties does not support the anomalous behaviour of boron ?
a) Small size
b) High electronegativity
c) High-ionisation energy
d) Formation of trihalides

13) Which cannot be prepared by B2H6 ?
a)
b)
c)
d)

14) Boron halides are
a) Used as refractory compounds
b) Ionic compounds
c) Electron deficient compounds
d) Lewis bases

15) Hydrogen forms a bridge in the chemical structure of
a) Hydrogen peroxide
b) Lithium hydride
c) Diborane
d) Sodium peroxide

16) Of the following Lewis acids, which one has triangular planar geometry and has zero dipole moment ?
a)
b)
c)
d)

17) Borax bead test is used for the identification of metals that form
a) White salts
b) Coloured salts
c) Hydrated salts
d) Acidic salts

18) The halides of IIIA group elements are
a) Lewis acids
b) Lewis bases
c) Bronsted acids
d) Arrhenius acids

19) Which of the following is not correct in the case of boron nitride ?
a) It is also called borazon
b) It is chemically unreactive
c) It is hard because it has diamond like structure
d) It has magnetic properties

20) Which is false in case of BF3 ?
a) It is volatile even at room temperature
b) It is a Lewis acid
c) It has planar geometry
d) It forms an adduct with NH3

21) B3+ ion is unknown because the
a) 1st, 2nd, 3rd I.E. are so high
b)
c)
d) All the above

22) Which of the following is a pure basic oxide?
a)
b)
c)
d)

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

24) Oxides of III group elements are generally
a) Acidic
b) Basic
c) Neutral halides
d) Amphoteric

25) The first ionization potential of Al is smaller than that of Mg because the
a) Atomic size of Al > Mg
b) Atomic size of Al. < Mg
c) Atomic number of Al < Mg
d) Al atom has electrons in the p-orbital

26) Sapphire contains
a)
b)
c)
d)

27) The metal which has no effect on a solution of mercury chloride is
a) Zn
b) Al
c) Fe
d) Ag

28) Alum is a
a) Double salt
b) Mixed salt
c) Normal salt
d) Complex salt

29) In aluminates the co-ordination number of Al is
a) 4
b) 6
c) 3
d) 1

30) Al becomes passive in
a)
b)
c)
d) All

31) Inorganic graphite is
a) BN
b)
c)
d)

32) With nitrogen, aluminium forms
a) AlN
b)
c)
d)

33) The main factor responsible for B-F bonds in BF3 is
a) Large electronegativity of F
b)
c)
d)

34) The reaction of aluminium with oxygen to form Al2O3 is
a) An exothermic reaction
b) An endothermic reaction
c) Reversible reaction
d) None of the above

35) Which of the following shows variable valency ?
a) B
b) Al
c) Ga
d) Tl

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

37) When Al is added to KOH solution,
a) No action takes place
b)
c)
d) Water is produced

38) In the electrolysis of alumina, cryolite is added to
a) Increase the m.p. of alumina
b) Increase the electrical conductivity
c) Minimise the anodic effect
d) Remove impurities from alumina

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

40) The alums contain
a) Any two metals
b) One bivalent and one trivalent metal
c) One monovalent and one trivalent metal
d) One monovalent and one bivalent metal

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

42) Which is not correct in the case of boric acid ?
a) It is a tribasic acid
b) It has a planar structure
c) It acts as a monobasic acid
d) It is soluble in hot water

43) An element R is in group III. Which is true in respect of R ?
a) It is a gas at room temperature
b) It has an oxidation state of +4
c)
d)

44) Boric acid is polymeric because
a) It is acidic in nature
b) It has hydrogen bonds present in it
c) It is monobasic
d) It is basic

45) Which of the following is a covalent compound ?
a) Aluminium oxide
b) Aluminium fluoride
c) Aluminium chloride
d) Aluminium sulphate

46) The reason for having two hydrogen bridge bonds in diborane is the
a) Presence of 14 electrons
b) Presence of 12 electrons
c) It has a two-electron deficiency than the required number of electrons
d) its having two electrons more than the required number of electrons

47) The stability of the +3 oxidation state in aqueous solutions is in the order
a) Al > Ga > In > TI
b) TI > In > Ga > Al
c) Al > Tl > Ga > In
d) TI > Al > Ga > In

48) The bonds present in borazole are
a)
b)
c)
d)

49) The three-centred electron pair bond is present in
a)
b)
c)
d) TiCI

50) Which of the following can not liberate H2 with acids?
a) Al
b) In
c) Tl
d) B

51) Red liquor is
a) Aluminium acetate
b) Aluminium hydroxide
c) Ammonium hydroxide
d) Magnesium aluminate

52) Which of the following contains a banana bond?
a)
b)
c)
d)

53) Which of the following is ionic ?
a)
b)
c)
d)

54) Borazole is more reactive than benzene, because
a) It is non-polar
b) It is polar
c) It is electron deficient
d) Of localised electrons in it

55) BCl3 is planar because of … hybridization.
a) sp
b)
c)
d)

56) BF3 is an example of a Lewis acid because it behaves as a/an
a) Nucleophile
b) Electrophile
c) Free radical
d) Lyophile

57) The hybridisation of boron in orthoboric acid is
a) sp
b)
c)
d)

58) Aluminium metal reduces many metallic oxides due to its great affinity for
a) Oxygen
b) Metals
c) Electrons
d) Hydrogen

59) The aluminothermacy is used in the preparation of the metal
a) Ti
b) W
c) Mo
d) All

60) Which of the following is not a Lewis acid ?
a)
b)
c)
d)

61) Which of the following statements is not correct ?
a)
b) Among B, Al and Tl, boron has the highest melting point because it has a giant molecular structure
c) Boron is the least metallic among B, Al, In and Ga
d) All are correct

62) Boron nitride on reacting with caustic alkali gives
a)
b)
c)
d)

63) Boric acid on heating at 150oC gives
a)
b)
c)
d)

64) Diborane reacts with water to form
a)
b)
c)
d)

65) The borax bead test is not given by
a) An aluminium salt
b) A cobalt salt
c) A copper salt
d) A nickel salt

66) An aqueous solution of BCl3 is a
a) Weak acid
b) Weak base
c) Neutral solution
d) Strong base

67) Al2O3 formation involves evolution of a large amount of heat, which is used in
a) Deoxidiser
b) Indoor photography
c) Confectionary
d) Thermite welding

68) Which of the following is a false statement?
a)
b)
c) Borax is used as a flux as well as a water softener
d)

69) Which of the following techniques is used in the manufacture of aluminium from bauxite ?
a) Reduction with Mg
b) Reduction with coke
c) Electrolytic reduction
d) Reduction with Fe

70) Solid oxy acids of boron are
a)
b)
c)
d) All

71) Which of the following oxyacid of boron is stable in aqueous solution ?
a)
b)
c)
d) None is stable

72) Which of the following statements is not correct ?
a)
b) Potash alum is used to stop bleeding
c)
d)

73) On strong heating ortho boric acid gives
a) Meta boric acid
b) Tetra boric acid
c) Boric anhydride
d) None

74) Which of the following is not correct ?
a)
b)
c)
d)

75) Which of the following is not correct ?
a) The slippery nature of boric acid is due to hydrogen bonding
b)
c)
d) All are correct

76) Which compound is used for fireproof cloth?
a)
b)
c)
d)

77) Which of the following is the correct increasing order of the acidic strength of BBr3, BF3 and BCl3?
a)
b)
c)
d)

78) A B—H—B bridge in diborane is formed by the sharing of
a) 2 electrons
b) 4 electrons
c) One electron
d) Three electrons

79) Which of the following undergoes sublimation ?
a)
b)
c) Dry ice
d) All

80) Which is more acidic?
a)
b)
c)
d)

81) AlCl3 exists as a dimer because
a) Al has greater I.P.
b) Al has a larger radius
c) of the high charge nucleus
d) of the incomplete p-orbital

82) Which of the following statements is correct ?
a)
b)
c)
d)

83) Which is not correct for H3BO3?
a) It is used as antiseptic
b) it is used as a preservative of foods
c) It gives a green colour to the flame
d) All are correct

84) Which of the following statement regarding H3BO3 is not correct ?
a) It is a strong tribasic acid
b) It is prepared by acidifying an aqueous solution of borax
c)
d)

85) The slippery nature of orthoboric acid is due to
a) Hydrogen bonding
b) Covalent bonds
c) its electron deficient nature
d) The layers held by van der Waals forces

86) In borazine
a)
b) the structure resembles that of diamond
c) The B-N distance in its structure is 144 pm
d) All are correct

87) Boron differs from other IHA group elements because of
a) the absence of the inert pair effect
b) Its high charge and small size
c) the absence of d-orbitals
d) All are correct

88) Aluminium is used as a reducing agent in the preparation of metals such as Cr, Mn, V etc. by the thermite process because
a) It has a high affinity for oxygen
b)
c) It reduces the oxides of these metals to metals
d) All are correct

89) Which of the following is not correct regarding anhydrous Al2O3?
a)
b)
c) It is used as a catalyst in Friedel Crafts reaction
d) All are correct

90) Which is not a correct statement?
a)
b)
c)
d) All are correct

91) Which of the following statements is not correct?
a) An aqueous solution of alum is acidic due to cationic hydrolysis
b) A mixture of Al powder in linseed oil is used as silver paint
c) All alums are isomorphous
d) All are correct

92) In the thermite mixture, along with Fe2O3 , the added substance is
a) Mg
b) Au
c) Al
d) Pt

93) The ignition mixture in the alumino thermite process contains a mixture of
a)
b)
c) Mg and Al powder
d) Mg and aluminium oxide

94) AlCl3 forms a dimer because
a) a higher co-ordination number can be achieved by Al
b) Al has high IE
c) Al belongs to III group
d) It cannot form a trimer

95) AlCl3 is
a) Anhydrous and covalent
b) Anhydrous and ionic
c) Covalent and basic
d) Co-ordinate and acidic

96) AlCl3 can be prepared when
a)
b)
c)
d)

97) The compound which is more acidic in water is
a)
b)
c)
d) None of these

98) Which metal burns in air at high temperature with the evolution of much heat?
a) Cu
b) Hg
c) Pb
d) Al

99) In diborane, a banana bond is formed between
a) 2 electrons and 3 atoms
b) 2 electrons, 1 atom
c) 2 electrons, 2 atoms
d) 1 electron, 2 atoms

100) Which of the following is used as a reducing agent in the thermite process?
a) Al
b) Fe
c) Mg
d) D


Answer

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