Solutions Question 9
Question 9 - 30 January - Shift 1
A solution containing $2 g$ of a non-volatile solute in $20 g$ of water boils at $373.52 K$. The molecular mass of the solute is__________ $g mol^{-1}$. (Nearest integer)
Given, water boils at $373 K, K_b$ for water $=0.52 K kg mol^{-1}$
Show Answer
Answer: (100g)
Solution:
$\Delta T_b=373.52-373$
$=0.52$
$\Delta T_b=Kb \cdot m$
$0.52=0.52 \times \frac{2}{\text{ Molar Mass }} \times \frac{1}{20 \times 10^{-3}}$
Molar Mass $=100 g / mol$
