Question

Elevation in boiling point was $0.52^{o}C$ when $6gm$ of a compound $X$ was dissolved in $100gm$ of water. Molecular weight of $X$ is $(K_{b}$ for water is 0.52 per 1000 gm of water)

• A. 120
• B. 60
• C. 180
• D. 600

Answer 1

Answer: (B)

60

Answer 2

$\Delta T_{b} = \frac{100 \times K_{b} \times w}{m \times W}$ ∴ $0.52 = \frac{100 \times 5.2 \times 6}{m \times 100}$

$m = \frac{100 \times 5.2 \times 6}{0.52 \times 100} = 60$.