Question

$1$ molal aqueous solution of an electrolyte $A_2{B}_3$ is $60\%$ ionised. The boiling point of the solution at $1atm$ is _____ K. (Rounded-off to the nearest integer) [Given $K_b$ for $\left(H_{2}O\right)=0.52Kkg{\left(mol\right)}^{-1}$ ]

Answer 1

Answer: 375

$A_2{B}_3\to 2A^{+3}+3B^{-2}$
No. of ions $=2+3=5$
$i=1+(n-1)\propto$
$=1+(5-1)\times 0.6$
$=1+4\times 0.6=1+2.4=3.4$
$\Delta T_b=K_b\times m\times i$
$=0.52\times 1\times 3.4=1.768^{\circ }C$
${\left(\Delta T\right)}_b={\left(T_b\right)}_{\text{solution }}-{\left(\left[{\left(T_b\right)}_{H_{2}O}\right]\right)}_{\text{Solution }}$
$1.768={\left(T_b\right)}_{\text{solution }}-100$
${\left(T_b\right)}_{\text{solution }}=101.768^{\circ }C$
$=375K$