
74. The correct order of ligands arranged in increasing
field strength.
(1) Cl– < –OH < Br– < CN–
(2) F– < Br– < I– < NH3
(3) Br– < F– < H2O < NH3
(4) H2O < –OH < CN– < NH3
Ans. (3)
Sol. Experimental order Br– < F– < H2O < NH3
75. Which of the following gives a positive test with
ninhydrin ?
(1) Cellulose (2) Starch
(3) Polyvinyl chloride (4) Egg albumin
Ans. (4)
Sol. Ninhydrin test is a test of amino acids. Egg
albumin contains protein which is a natural
polymer of amino acids which will show positive
ninhydrin test
76. The metal that shows highest and maximum
number of oxidation state is:
(1) Fe (2) Mn
(3) Ti (4) Co
Ans. (2)
Sol. Mn shows highest oxidation state (Mn+7) in 3d
series metals.
77. Ail organic compound has 42.1% carbon, 6.4%
hydrogen and remainder is oxygen. If its molecular
weight is 342, then its molecular formula is :
(1) C11H18O12 (2) C12H20O12
(3) C14H20O10 (4)
C12H22O11
Ans. (4)
Sol. only C12H22O11 has 42.1% carbon, 6.4% hydrogen
& 51.5 percent oxygen.
78. Given below are two statement :
Statement I : Bromination of phenol in solvent
with low polarity such as CHCl3 or CS2 requires
Lewis acid catalyst.
Statement II : The lewis acid catalyst polarises the
bromine to generate Br+.
In the light of the above statements, choose the
correct answer from the options given below :
(1) Statement I is true but Statement II is false.
(2) Both Statement I and Statement II are true
(3) Both Statement I and Statement II are false.
(4) Statement I is false but Statement II is true.
Ans. (4)
Sol. Phenol is a highly activated compound which can
undergo bromination directly with Bromine
without any lewis acid.
79. Molar ionic conductivities of divalent cation and
anion are 57 S cm2 mol–1 and 73 S cm2 mol–1
respectively. The molar conductivity of solution of
an electrolyte with the above cation and anion will
be :
(1) 65 S cm2 mol–1 (2) 130 S cm2 mol–1
(3) 187 S cm2 mol–1 (4) 260 S cm2 mol–1
Ans. (2)
Sol.
22
Solution C A
= 57 + 73 = 130
80. The number of neutrons present in the more abundant
isotope of boron is 'x'. Amorphous boron upon
heating with air forms a product, in which the
oxidation state of boron is 'y'. The value of x + y is …
(1) 4 (2) 6
(3) 3 (4) 9
Ans. (4)
Sol. More abundant isotope = B11
[Number of neutrons = 6]
x = 6
B + O2 B2O3
Oxidation state of B in B2O3 = +3
So, y = 3
Hence x + y = 9
SECTION-B
81. The value of Rydberg constant (RH) is 2.18×10–18 J.
The velocity of electron having mass 9.1×10–31 kg
in Bohr's first orbit of hydrogen atom
= ……… ×105 ms–1 (nearest integer)
Ans. (22)
Sol. V = 2.18 × 106 ×
= 21.8 × 105 ×
22 × 105 (nearest)