The elevation in boiling point of a solution of $10 \mathrm{~g}$ of a binary electrolyte (of molecular mass…
The elevation in boiling point of a solution of $10 \mathrm{~g}$ of a binary electrolyte (of molecular mass 100) in $100 \mathrm{~g}$ of water is $\Delta T_b$. Then, the value of $K_b$ for water is
$\frac{\Delta T_b}{2}$
10
$10 \Delta T_b$
$\frac{\Delta T_b}{10}$
Solution
Weight of solute $=10 \mathrm{~g}$
Weight of solvent $=100 \mathrm{~g}$
Molecular mass of electrolyte $=100$
$
\begin{aligned}
\Delta T_b & =i \times K_b \times \frac{\text { wt. of solute }}{\text { molecular mass }} \times \frac{1000}{\text { wt. of solvent }} \\
& =2 \times K_b \times \frac{10}{100} \times \frac{1000}{100}
\end{aligned}
$
$
\begin{aligned}
\Delta T_b & =2 \times K_b \\
K_b & =\frac{\Delta T_b}{2}
\end{aligned}
$