An organic liquid, A, is immiscible with water. When boiled together with water, the boiling point is 90° C at which the partial vapour pressure of water is 526 mm Hg. The atmospheric pressure is 736 mm H g. The weight ratio of the liquid and water collected is 2.5: 1. What is the molecular weight of the liquid?

Question

An organic liquid, A, is immiscible with water. When boiled together with water, the boiling point is 90° C at which the partial vapour pressure of water is 526 mm Hg. The atmospheric pressure is 736 mm H g. The weight ratio of the liquid and water collected is 2.5: 1. What is the molecular weight of the liquid? (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

( P L / P H 2 O )=( n L / n H 2 O ) (736-526/526)=( W L / M L / W H 2 O / 18) (210/526)=(2.5/ M L ) × 18 M L =112.7 gm

PH2​O​PL​​=nH2​O​nL​​ 526736−526​=WH2​O​/18WL​/ML​​ 526210​=ML​2.5​×18 ML​=112.7gm

$\frac{P _{L}}{P _{H_{2} O}} = \frac{n _{L}}{n _{H_{2} O}}$
$\frac{736 - 526}{526} = \frac{W _{L} / M _{L}}{W _{H_{2} O} /18}$
$\frac{210}{526} = \frac{2.5}{M _{L}} \times 18$
$M_{L} = 112.7 g m$