Q13 / 160 · TS EAMCET 2015 · Chemistry
An aqueous dilute solution containing non-volatile solute boils at $100.52^{\circ} \mathrm{C}$. What is the molality of solution?
$\left(K_b=0.52 \mathrm{~kg} \mathrm{~mol}^{-1} \mathrm{~K}\right.$, boiling temperature of water $=100^{\circ} \mathrm{C}$ )
- Correct answerA$0.1 \mathrm{~m}$
- B$0.01 \mathrm{~m}$
- C$0.001 \mathrm{~m}$
- D$1.0 \mathrm{~m}$
Solution
$\Delta T_b=K_b \cdot m$
$$
T_b-T_b^{\circ}=K_b \cdot m
$$
where, $K_b=$ molal elevation constant $m=$ molality
$$
\begin{aligned}
(100.052-100.00) & =(0.52)(m) \\
0.052 & =0.52 \times m \\
m & =0.1
\end{aligned}
$$
Hence, the correct answer is option: 'A'.