Question

3.
Give reactivity order towards EAR.
​

Answer 1

Answer:

The order of reactivity towards electrophilic addition reaction depends upon the electron donating ability of the groups attached to the cyclohexene ring. Order of electron donating power: Cl>OH>CH

3

Answer 2

Answer:

The correct option is 3. (ii)>(iv)>(i)>(iii)

Explanation:

CONCEPT:

1)Order of priority for electron donating/receiving group is.

MESOMERIC EFFECT>RESONANCE>HYPERCONJUGATION>INDUCTIVE

(NOTE that MESOMERIC AND HYPERCONJUGATION are also a type of resonance)

2) Rate of E.A.R is proportional to electron donating ability of the compond.

In ii) Oxygen is having +M effect on the conjugation. (electron donating)

   vi)$CH_{3}$ group is having an  extra hyperconjugation than in case (i)

   iii)chlorine (Cl) is having +M and -M both.But here +M slighty dominates    -M hence it showing partial +M effect and also INDUCTIVE EFFECT (-I).

As a result chlorine lies between case (vi) and case (i).

Hence, the correct order is (ii)>(iv)>(i)>(iii)