Question

If $0.15g$ of a solute dissolved in $15g$ of solvent is boiled at a temperature higher by $0.216^{o}C$ than that of the pure solvent. The molecular weight of the substance (molal elevation constant for the solvent is $2.16^{o}C$) is.

• A. 1.01
• B. 10
• C. 10.1
• D. 100

Answer 1

Answer: (D)

100

Answer 2

$m = \frac{K_{b} \times w \times 1000}{\Delta T_{b} \times W} = \frac{2.16 \times 0.15 \times 1000}{0.216 \times 15}$= 100 .