
SECTION-A
61. Given below are two statements:
Statement-I: The gas liberated on warming a salt
with dil H2SO4, turns a piece of paper dipped in
lead acetate into black, it is a confirmatory test for
sulphide ion.
Statement-II: In statement-I the colour of paper
turns black because of formation of lead sulphite.
In the light of the above statements, choose the
most appropriate answer from the options given
below:
(1) Both Statement-I and Statement-II are false
(2) Statement-I is false but Statement-II is true
(3) Statement-I is true but Statement-II is false
(4) Both Statement-I and Statement-II are true.
Ans. (3)
Sol. Na2S + H2SO4 Na2SO4 + H2S
(CH3COO)2Pb + H2S PbS + 2CH3COOH
Black lead
sulphide
62.
This reduction reaction is known as:
(1) Rosenmund reduction
(2) Wolff-Kishner reduction
(3) Stephen reduction
(4) Etard reduction
Ans. (1)
Sol.
It is known as rosenmund reduction that is the
partial reduction of acid chloride to aldehyde
63. Sugar which does not give reddish brown precipitate
with Fehling‟s reagent is:
(1) Sucrose (2) Lactose
(3) Glucose (4) Maltose
Ans. (1)
Sol. Sucrose do not contain hemiacetal group.
Hence it does not give test with Fehling solution.
While all other give positive test with Fehling
solution
64. Given below are the two statements: one is labeled as
Assertion (A) and the other is labeled as Reason (R).
Assertion (A): There is a considerable increase in
covalent radius from N to P. However from As to
Bi only a small increase in covalent radius is
observed.
Reason (R): covalent and ionic radii in a particular
oxidation state increases down the group.
In the light of the above statement, choose the
most appropriate answer from the options given
below:
(1) (A) is false but (R) is true
(2) Both (A) and (R) are true but (R) is not the
correct explanation of (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are true and (R) is the correct
explanation of (A)
Ans. (2)
Sol. According to NCERT,
Statement-I : Factual data,
Statement-II is true.
But correct explanation is presence of completely
filled d and f-orbitals of heavier members