Question

0.3 molal aqueous solution of $CuC{l}_2$ is $75\%$ ionized. If $K_b$ for water is $0.52Kkgmo{l}^{-1}$, the elevation in boiling point of solution is:

• A. 0.39 K
• B. ${0.39}^{\circ }C$
• C. Both (A) and (B)
• D. None of these

Answer 1

The correct option is C Both (A) and (B)

$\Delta T_b=i\times K_b\times m$
$i=1+(n-1)\alpha$
for $CuC{l}_{2}n=3,\alpha =\frac{3}{4}$
$=1+\left(2\right)\times \frac{3}{4}=\frac{5}{2}$
$\Delta T_b=\frac{5}{2}\times 0.52\times 0.3=0.39Kor{0.39}^{\circ }C$