Calculate the molarity and molality of 20 percent aqueous ethanol solution by volume and density of solution 0.960 g per cm 3
Answers
Answered by
3
ANSWER:
C
2
H
5
OH is 20% by volume i.e. 20 mL of C
2
H
5
OH is dissolved in 100 mL of solution.
Volume of H
2
O=100−20=80 mL
Weight of H
2
O=80×1=80 g (d
H
2
O
=1 g/cc)
Weight of solution =100×0.96=96 g
Weight of C
2
H
5
OH=96−80=16 g
Molecular weight of C
2
H
5
OH=12×2+5+16+1=46 g/mol
M=
Mw
2
×V
sol
W
2
×1000
=
46×100
16×1000
=3.48M
m=
Mw
2
×W
1
W
2
×1000
=
46×80
16×1000
=4.35m
Hence, option B is correct.
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