Question

What is/are the required reagent for the following reaction:

• A. $H_{2}S{O}_4$
• B. $S{O}_3$ and $H_{2}S{O}_4$ (fuming)
• C. $S{O}_3$
• D. All of the above.

Answer 1

The correct option is B $S{O}_3$ and $H_{2}S{O}_4$ (fuming)

Sulphonation : The replacement of H atom by sulfonic acid group in the benzene ring.
It is carried out by heating benzene with fuming sulphuric acid (oleum).
Hence, correct option is b.