Name: Structure of Benzene
Uploaded: 2019-07-19
Duration: 3 min 53 s
Description: Benzene is the most commonly known aromatic compound and is a significant part of gasoline. In this video, we will study the structure and properties of benz...

Question

Explain electrophilic addition reactions of ethylene with mechanism.

Accepted Answer

1) Addition of halogens : Ethylene combines with halogens at room temp.in an inert solvent medium, to give a vicinal dihalide.
Ex : Bromination.

$\underset{Ethylene}{{CH}_{2} = {CH}_{2}} + {Br}_{2} \to \underset{\underset{(Vicinal dihalide)}{1, 2 - dibromoethane}}{{CH}_{2} Br - {CH}_{2} Br}$

Mechanism : It involves 2 steps.
Step (I) : The π- electrons of the double bond attack the halogen molecule.

Step (II): The negative bromide ion attacks the cyclic bromonium ion from the backside.
This is called, 'trans' addition of halogens.

2) Addition of hydrogen halide: Ethylene reacts with hydrogen halide $(HX)$ to give ethyl halide.

Example: $\underset{Ethylene}{{CH}_{2} = {CH}_{2}} + HX \to \underset{Ethyl halide}{{CH}_{3} {CH}_{2} X}$

Mechanism : This mechanism is quite similar to that of the halogen addition, involving 2 steps.

3) Addition of hypohalous acid to ethylene : Ethylene reacts with hypochlorous acid to give ethylene chlorohydrin.

$\underset{Ethylene}{{CH}_{2} = {CH}_{2}} + HOCl \to \underset{Ethylene chlorohydrin}{\underset{\underset{OH}{I}}{C} H_{2} - \underset{\underset{Cl}{I}}{C} H_{2}}$

Mechanism :
The same mechanism as in the case of addition of $HX$ .

$HX \to H^{+} + X^{-}$

In $HOCl$ , the $Cl$ adds first. Then ${OH}^{-}$ adds to the carbon atom.

Explain electrophilic addition reactions of ethylene with mechanism.

Important Questions on Hydrocarbons

Learn and Prepare for any exam you want !