Question

The mole fraction of ethanol in $4$ molal solution is:

• A. $0.67$
• B. $0.0674$
• C. $0.034$
• D. $0.34$

Answer 1

Answer: (B)

$0.0674$

4 moles of ethanol present in 1000 gm of solvent $\left(H_{2}O\right)$.

Moles of water $=\frac{1000}{18}=55.5moles$

Mole fraction of $C_2{H}_{5}OH$ = $\frac{Molesofethanol}{Molesofethanol+molesofwater}$

= $\frac{4}{4+55.5}$

= $\frac{4}{59.5}$

= $0.067$
Hence, option $\left(B\right)$ is correct.