Question

Write short note on chlorination of methane

Answer 1

Answer:

CHLORINATION OF METHANE;

The reaction is between methane and chlorine in the presence of ultraviolet light - typically sunlight.

CH4+Cl2→CH3Cl+HCl

The organic product is chloromethane. One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction.

The Mechanism

The mechanism involves a chain reaction.

During a chain reaction, for every reactive species you start off with, a new one is generated at the end - and this keeps the process going. The over-all process is known as free radical substitution, or as a free radical chain reaction.

Chain initiation: The chain is initiated (started) by UV light breaking a chlorine molecule into free radicals.

Cl2 →→ 2Cl

Chain propagation reactions : These are the reactions which keep the chain going.

CH4 + Cl→→CH3 + HCl

CH3 + Cl2→→CH3Cl + Cl

Chain termination reactions: These are reactions which remove free radicals from the system without replacing them by new ones.

2Cl→→Cl2

CH3 + Cl →→ CH3C l

CH3 + CH3→→CH3CH3

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