1. Use elevation in boiling point formula

For a solution, $\Delta T_b = i K_b m$ where:

• $i$ = van’t Hoff factor
• $K_b = 0.52\ \text{K kg mol}^{-1}$
• $m = 1$ molal

2. Find van’t Hoff factor

Electrolyte: $A_2B_3$

On complete ionisation: $A_2B_3 \rightarrow 2A^{3+} + 3B^{2-}$ So total ions formed $= 5$.

Given degree of ionisation: $\alpha = 60\% = 0.6$

For an electrolyte giving $\nu$ ions, $i = 1 + (\nu - 1)\alpha$

Here $\nu = 5$, so $i = 1 + (5-1)(0.6) = 1 + 2.4 = 3.4$

3. Calculate elevation in boiling point

$\Delta T_b = i K_b m = 3.4 \times 0.52 \times 1 = 1.768\ \text{K}$

4. Find boiling point of solution

Normal boiling point of water at 1 atm is $373\ \text{K}$

Hence, $T_b = 373 + 1.768 = 374.768\ \text{K}$

Rounded to nearest integer: $\boxed{375\ \text{K}}$

5. Comparison with stored answer

Stored correct answer = $375$

Our derived answer matches the stored answer.