Question

Arrange the following in the increasing order of reactivity towards sulphonation with fuming sulphuric acid:
Benzene, toluene, methoxybenzene, chlorobenzene.

• A. Chlorobenzene < Benzene < Toluene < Methoxy benzene.
• B. Toluene < Methoxy benzene<Chlorobenzene < Benzene
• C. Toluene < Methoxy benzene<Chlorobenzene < Benzene
• D. Chlorobenzene < TolueneBenzene < Methoxy benzene.

Answer 1

The correct option is A Chlorobenzene < Benzene < Toluene < Methoxy benzene.

Sulphonation is electrophillic substitution reaction, more strong electron donating group present on ring more is the reactivity.
The correct order of electron donating ability is $\text{(Methoxy)}-OC{H}_3>\text{(Alkyl group)}-C{H}_3>(\text{(Hydrogen)}H>(\text{(Chlorine)}Cl$
The correct order of reactivity is:
Chlorobenzene < Benzene < Toluene < Methoxy benzene.