Question

Sulphonation of phenol at low temperature gives

• A. 2-phenol sulphonic acid, a major product
• B. 4-phenol sulphonic add, a major product -
• C. Both (a) and (b)
• D. None of the above

Answer 1

Answer: (A)

Sulphonation of phenol, gives a mixture of ortho and para isomers. If sulphonation is carried out at low temperature, kinetically controlled ortho-isomer is the chief product and if sulphonation is carried out at high temperature, thermodynamically controlled para-isomer is the chief product.