Answer:
The first step in the free radical mechanism for the preparation of polyethylene is:
b. heating an organic peroxide to break the O-O bond
Explanation:
The preparation of ethylene occur by free radical mechanism , which occurs in three steps :
1. Chain Initiation
2. Chain propagation
3. Chain termination.
The first step i.e chain initiation require a radical. The compound are generally peroxide(O-O linkage) that produce radical is :
Benzoyl Peroxide
This compound when heated (with U.V radiation) produce two species of radicals .
(see the attached image)
These RADICALS are highly unstable and very reactive in nature.
They readily react with ethene and initiate the polymerisation.
Thus,
The first step in the free radical mechanism for the preparation of polyethylene is:
b. heating an organic peroxide to break the O-O bond
The sequence of Polymerisations are:
b. heating an organic peroxide to break the O-O bond
d. propagation of the free radicals