Question

1 g of non-volatile non-electrolyte solute is dissolved in 100g of two different solvents A and B whose ebullioscopic constants are in the ratio of 1 : 5. The ratio of the elevation in their boiling points, $\frac{\Delta T_b(A)}{\Delta T_b (B)}$, is:

• A. 5 : 1
• B. 10 : 1
• C. 1 : 5
• D. 1 : 0.2

Answer 1

Answer: (C)

$\Delta T_{b} = K_{b} \times m $
$ \therefore \frac{\Delta T_{b\left(A\right)}}{\Delta T_{b\left(B\right)}} = \frac{K_{b\left(A\right)}}{K_{b\left(B\right)}} as m_{A} =m_{B} $
$ \therefore \frac{\Delta T_{b\left(A\right)}}{\Delta T_{b\left(B\right)}} = \frac{1}{5} $