Question

Arrange following compounds in decreasing order of reactivity of ring towards attack of electron deficient species.

• A. $i>ii>iii>iv$
• B. $iii>iv>ii>i$
• C. $i>iv>ii>iii$
• D. $i>ii>iv>iii$

Answer 1

The correct option is D $i>ii>iv>iii$

More number of electron donating groups present on ring, higher the reactivity towards electron-deficient species.

Toluene will have the highest reactivity due to the presence of three alpha hydrogens which will lead to pronounced $+H$ effect.

Since the number of alpha hydrogens decrease in the order $i)>ii)>iv)>iii)$,

The same order will be followed reactivity towards electrophillic species.

Option D is correct.