Question

Give the possible structure of X in the following reaction: C₆H₆ + D₂SO₄ [D₂O] X 

• A. Benzene–SO₃D
• B. Monodeuterated benzene with SO₃D group
• C. Benzene–SO₃H with one D on ring
• D. Hexadeuterobenzene

Hint:

Strong deuterated acids can cause both substitution and H–D exchange in aromatic rings.

Answer 1

The Correct Option is B

Step 1: Reaction of benzene with D₂SO₄ causes sulphonation.
Step 2: In presence of D₂O, electrophilic aromatic substitution also leads to H–D exchange on the ring.
Step 3: Hence product is a sulphonated benzene containing one deuterium atom on the ring and SO₃D group.