Two compounds A and B forms non-volatile compounds having molecular formulae AB2 and AB4. when 1 g of AB2 and 1g of AB4 are separately dissolved in 20 g of Benzene, the B.P. was lowered by 2.3∘C and 1.3∘C respectively. Find the molar mass of A and B. kb of Benzene is S.1 k kg/mol
MA=25.60g,MB=42.65g
2.3=1(MA+2MB)×100020×5.1−(1)1.3=1(MA+4MB)×100020×5.1−(2)
Solving (1) & (2) gives
MA=25.60 g and MB=42.65g