Q.

0.01 mole of an organic compound (X) containing 10% hydrogen, on complete combustion produced 0.9 g H2O. Molar mass of (X) is ______ g mol-1.                         [2025]


Ans.

(100)

Moles of water = Given mass of H2OMolar mass of H2O=0.918mol=0.05 mol 

Moles of H =2×moles of water=2×0.05mol=0.1mol

Mass of H = Moles of H×molar mass of H=0.1×1 g=0.1 g

So 0.1 g H is present in 0.01 mol of an organic compound. Thus 10 g of H is present in 1 mol of the compound.

% of H=Mass of H in 1 mol compoundMolar mass of compound×100

10=10Molar mass of compound×100

Molar mass of compound = 100 g mol-1