In the following reaction

The % yield for reaction I is 60% and that of reaction II is 50%. The overall yield of the complete reaction is ___% [nearest integer]

(I)

Let initial moles of reactant taken = n

Total moles obtained for benzene sulphonic acid (with % yield = 60%) = 0.6n

(II)

Moles of benzene sulphonic acid before reaction II = 0.6n

Moles obtained for phenol (with % yield = 50%) = 0.6 × 0.5 n =0.3 n

So over all % yield of complete reaction$=\frac{0.3\mathrm{n}}{\mathrm{n}}\times 100=30$