Ratio of Δ T b K b of 10 g AB 2 and 14 g A 2 B per 100 g of solvent in their respective, solution (AB 2 and A 2 B both are non-electroytes) is 1 mol/kg in both cases. Hence, atomic wt. of A and B are respectively :

Step-by-step solution

Δ T b = K b w solute W solvent × 1 M solute × 1 0 0 0 1 = 1 0 0 0 × 1 0 1 0 0 × M AB 2 ⇒ M AB 2 = 1 0 0 Similarly M A 2 B = 1 4 0 1 0 0 = M A + 2 · M B and 1 4 0 = 2 · M A + M B ; M A = 6 0 and M B = 2 0 Alternative solution Δ T b K b = 1 = 1 0 M A + 2 M B 0.1 M A + 2 M B = 1 0 0 ........ (1) Δ T b K b = 1 = 1 4 2M A + M B 0.1 2 M A + M B = 1 4 0 ........ (2) M A = 60, M B = 2 0