Question

Dry air was passed successively through a solution of $5gm$ of a solute in $80gm$ of water and then through pure water. The loss in weight of solution was $2.50gm$ and that of pure solvent $0.04gm$. What is the molecular weight of the solute.

• A. 70.31
• B. 7.143
• C. 714.3
• D. 80

Answer 1

Answer: (A)

70.31

Answer 2

$m = \frac{5 \times 18 \times 2.5}{0.04 \times 80} = 70.31$