Question

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]

Answer 1

Answer: 30

Let initial moles of reactant taken $=n$
Total moles obtained for benzene sulphonic acid $($ with $\%$ yield $=60\%)=0.6n$

Moles of benzene sulphonic acid before reaction II $=0.6n$
Moles obtained for phenol (with $\%$ yield $=50\%$ ) $=0.6\times 0.5n=0.3n$
So over all \% yield of complete reaction $=\frac{0.3n}{n}\times 100=30$