Question

Phenol on treating with concentrated $H_{2}S{O}_4$ at $15-{20}^{0}C$ mainly produces :

• A. phenol-2,4,6-trisulphonic acid
• B. 2-hydroxy benzene sulphonic acid
• C. phenol-4-sulphonic acid
• D. a 50% mixture of ortho and para phenolsulphonic acid

Answer 1

The correct option is B 2-hydroxy benzene sulphonic acid

The product of the reaction of phenol with conc. sulphuric acid depends upon the temperature of the reaction.

When phenol is treated with conc $H_{2}S{O}_4$ at $15-{20}^{o}C$, o-phenol sulphonic acid is obtained as the major product.

But when phenol is treated with conc. $H_{2}S{O}_4$ at ${100}^{o}C$, p-phenol sulphonic acid is obtained as the major product.

Option B is correct.