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Question
Chemistry
Calculate the molality of a solution that contains 51.2 g of naphthalene. (C10H8), in 500 mL of carbon tetrachloride. The density of CCI4 is 1.60 g/mL
Q. Calculate the molality of a solution that contains
51.2
g
of naphthalene.
(
C
10
H
8
)
, in
500
m
L
of carbon tetrachloride. The density of
CC
I
4
is
1.60
g
/
m
L
2072
222
KEAM
KEAM 2016
Solutions
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A
0.250,
m
8%
B
0.500
m
62%
C
0.750
m
8%
D
0.840
m
12%
E
1.69
m
12%
Solution:
Given,
W
B
=
mass of naphthalene
=
51.2
g
M
B
=
molar mass of naphthalene
(
C
10
H
8
)
=
12
×
10
+
8
=
128
g
W
A
=
density
(
d
)
×
volume
(
V
)
(
∵
d
=
V
w
)
W
A
=
1.60
g
m
L
−
1
×
500
M
L
=
800
g
∵
m
=
M
B
W
B
×
(
W
A
(
k
g
)
1000
)
m
=
128
×
800
51.2
×
1000
=
0.5
m