In the following reaction The % yield for reaction I is 60 % and...

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 $= \dfrac{0 . 3n}{n} \times 100 = 30$