Question

Lowering of vapour pressure of an aqueous solution of a non-volatile, non-electrolyte $1M$ aqueous solution at $373K$ is____________.

• A. $0.020$ bar
• B. $0.018$ bar
• C. $0.012$ bar
• D. $0.026$ bar

Answer 1

The correct option is A $0.020$ bar

Relative lowering of V.P

$\frac{P^0-P}{P^0}=X_i=$mole fraction

$P^0-P=\Delta P=X_i\times P^0$

$=\left(\frac{1}{1+\frac{1000}{18}}\right)$ bar

= $\frac{1}{1+55.55}$ bar

$=0.0176$ or $0.02$ bar

Hence, the correct option is $\text{A}$