Question

The electrophile involved in the sulphonation of benzene is

• A. $SO_{3}^{+}$
• B. $SO_{3}^{2-}$
• C. $H_{3}^{+}O$
• D. $SO_{3}$

Hint:

Sulphonation uses neutral $SO_{3}$ as the electrophile.

Answer 1

The Correct Option is D

Step 1: Reaction Mechanism
In the sulphonation of benzene, concentrated sulphuric acid reacts with itself to produce the reactive species.
Step 2: Species Generation
$2H_{2}SO_{4} \longrightarrow SO_{3} + H_{3}O^{+} + HSO_{4}^{-}$.
Step 3: Identification
The neutral $SO_{3}$ molecule acts as the electrophile because the sulphur atom is highly electron-deficient due to the three electronegative oxygen atoms.
Final Answer: (d)