Chemistry_Today_April_2017_vk_com_stopthepress

tension, viscous force, weight but Newton’s laws are
not applicable, when velocity of an object comparable
to the velocity of light and microscopic particle. If the
system contains large number of particles, then if we
apply the Newton’s laws, concept of centre of mass is
included.
17. Pulley and strings are
massless. The force
T T
acting on the block of
T T
F
mass m
m
F
(a) 2F (b) F (c) (d) 4F
2
18. A particle of mass m moves along a circle of radius
R. The modulus of average value of force acting
on particle over the distance equal to a quarter of
circle, if the particle moves uniformly with velocity
v is
(a) 2 mv 2 /r (b) 2 2mv 2 /r 2
(c) 2 2mv 2 /r (d) mv 2 /r
CHEMISTRY
SECTION 1 (Maximum Marks : 18)
• This section contains SI questions.
• Each question has FOUR options (a), (b), (c) and (d). ONLY ONE
of these four options is correct.
• For each question, darken the bubble corresponding to the
correct option in the ORS.
• For each question, marks will be awarded in one of the following
categories :
Full Marks : +3 If only the bubble corresponding to the correct
option is darkened.
Zero Marks : 0 If none of the bubbles is darkened.
Negative Marks : –1 In all other cases.
19. In the button cell widely used in watches and other
devices, the following reaction takes place :
Zn (s) + Ag 2 O (s) + H 2 O (l) Zn 2+
(aq) + 2Ag (s) +
2OH – (aq)
What will be the value of D r G° for the reaction?
(Given : Zn 2+ + 2e – Zn, E° = – 0.76 V;
Ag 2 O + H 2 O + 2e – 2Ag + 2OH – , E° = 0.344 V)
(a) –8.02 × 10 4 J (b) 1.60 × 10 5 J
(c) –2.13 × 10 5 J (d) 4.26 × 10 5 J
20. Consider the following reaction,
(c)
(d)
O
21. End product of the following sequence of reactions,
HC CH
(i)CO 2
(ii)H 3 O+
HgSO 4/H2SO4 Ag 2 O
CH MgBr 3
HC CMgBr
is
(a) CH3
O
C COOH
O
(c) CH3
C CHO
(b) CH 2 (COOH) 2
O
(d) H C CHCOOH 2
OH
22. When
undergoes dehydration
reaction in presence of concentrated H 2 SO 4 then
what will be the major product?
(a)
(c)
(b)
(d)
23. Which of the following statements is not correct
from the view point of molecular orbital theory?
(a) Be 2 is not a stable molecule.
(b) He 2 is not stable but He + 2 is expected to exist.
(c) Bond strength of N 2 is maximum amongst the
homonuclear diatomic molecules belonging to
the second period.
(d) The order of energies of molecular orbitals
in N 2 molecule is 2s < *2s < 2p z < 2p x
= 2p y < *2p x = *2p y < *2p z .
24. In the reaction,
HC 3 C
O
(i) NaOH/Br 2
O
NH 2 (ii) C
Cl
the structure of the product T is
O
(a) HC 3 C O
O C
T
‘A’ is
(a)
CH Br 2 O
CH PPh 2 3
O
PPh 3
(b)
‘ A’
(b)
NH
C
O
(c) HC 3 C
CH 3
O
O
NH C
74 CHEMISTRY TODAY | APRIL ‘17