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21. Based upon the following hypothetical equilibrium
at 273 K
(i) XCl 2 ⋅ 6H 2 O (s) XCl 2 ⋅ 2H 2 O (s) + 4H 2 O (g) ;
K p = 8.1 × 10 –11 atm 4
(ii) Y 2 HPO 4 ⋅ 12H 2 O (s) Y 2 HPO 4 ⋅ 7H 2 O (s) + 5H 2 O (g) ;
K p = 3.2 × 10 –9 atm 5
(iii) Z 2 SO 4 ⋅ 10H 2 O (s) Z 2 SO 4(s) + 10H 2 O (g) ;
K p = 1.0 × 10 –30 atm 10
Which is the most effective dehydrating agent at
273 K? (Aqueous tension at 273 K = 6.0 × 10 –3 atm)
(a) XCl 2 . 6H 2 O (s) (b) Y 2 HPO 4 . 7H 2 O (s)
(c) Z 2 SO 4(s)
(d) Z 2 SO 4 . 10H 2 O (s)
22. The correct IUPAC name for is
(a) 5-methyl-4-(1’-2’-dimethylpropyl)heptane
(b) 3-methyl-4-(1’, 2’-dimethylpropyl)heptane
(c) 2, 3, 5-trimethyl-4-propylheptane
(d) 4-propyl-2, 3, 5-trimethylheptane.
23. Electrolysis of NaCl solution with inert electrodes
for certain period of time gave 600 cm 3 of 1.0 M
NaOH in the electrolytic cell. During the same
period, 31.80 g of copper was deposited in a copper
voltameter in series with the electrolytic cell.
What is the percentage of current efficiency in the
electrolytic cell? (At. wt. of Cu = 63.6)
(a) 40 (b) 50 (c) 60 (d) 25
24. Aluminium displaces hydrogen from dilute HCl
whereas silver does not. The emf of a cell prepared
by combining Al/Al 3+ and Ag/Ag + is 2.46 V. The
reduction potential of silver electrode is +0.80 V.
The reduction potential of aluminium electrode is
(a) + 1.66 V
(b) – 3.26 V
(c) + 3.26 V
(d) – 1.66 V
25. The hybridisation, oxidation number and shape
of central metal ion of Wilkinson’s catalyst are
respectively
(a) dsp 2 , +1, square planar
(b) sp 3 , +4, tetrahedral
(c) sp 3 d, +2, trigonal bipyramidal
(d) d 2 sp 3 , +6, octahedral.
26. Consider the following reaction,
HO
CH 3
CH 3
HC
3
H + A
Here, A is
(a)
(c)
CH 3
CH 3
(b)
CH 3
CH 3
(d)
HC 3
HC 3
CH 3
27. Consider the following reactions,
k1
k
A + B ↽
⇀
C, C + B 2→
D
k−1
The rate in terms of − dB [ ] will be
dt
(a) k 1 [A][B] – k –1 [C]
(b) k 1 [A][B] – k 1 [C] – k 2 [C][B]
(c) k 1 [A][B] – k 2 [C][B]
(d) k 1 [A][B] – k –1 [C] + k 2 [C][B]
CH 3
CH 3
CH 3
28. 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 soluble
aluminate
(d) washing soda reacts with Al to form insoluble
aluminium oxide.
29. When I 2 is passed through KCl, KF, KBr
(a) Cl 2 and Br 2 are evolved
(b) Cl 2 is evolved
(c) Cl 2 , Br 2 , F 2 are evolved
(d) none of these.
30. Zeta potential (or electrokinetic potential) is
the
(a) potential required to bring about coagulation
of a colloidal sol
(b) potential required to give the particles a speed
of 1 cm/sec in the sol
(c) potential difference between fixed charged layer
and the diffused layer having opposite charges
(d) potential energy of the colloidal particles.
31. Gadolinium belongs to 4f series and its atomic
number is 64. Which of the following is the correct
electronic configuration of gadolinium?
(a) [Xe]4f 9 5s 1 (b) [Xe]4f 7 5d 1 6s 2
(c) [Xe]4f 6 5d 2 6s 2 (d) [Xe]4f 8 5d 2
7 1
32. In the nuclear reaction, 3 Li + 1H → 2 4
2 He , the
mass loss is nearly 0.02 amu. Hence, the energy
released (in million kcal/mol) in the process is
approximately
(a) 428 (b) 200 (c) 100 (d) 50
CHEMISTRY TODAY | APRIL ‘17 33