Question

List the following alkenes in decreasing order of reactivity towards electrophilic addition:
(i) $ClCH_{2}CH$=$CH_{2}$
(ii) $(CH_{3})_{2}=CH_{2}$
(iii) $CH_{3}CH$=$CH_{2}$
(iv) $CH_{2}$=CHCl
Explain your answer.

Answer 1

In the alkyl groups, donation of electrons makes the  π bond to be more reactive and also rich in the electron. Conversely, the electron withdrawing alkyl groups like Cl makes the π bond to be less reactive and also electron deficient.

The reactivity in the electrophillic addition in decreasing order,

1. $(CH_3 )_2=CH_2$ (Since two CH_3 group)

2. $(CH_3)CH=CH_2$(Since one CH_3 group)

3. $ClCH_2 CH=CH_2$(Alkyl with Cl)

4. $CH_2=CHCl$(Cl is bonded to carbon double bond)