Question

Which one of the following is a free-radical substitution reaction:

• A.
• B.
• C.
• D. CH₃CHO+HCN\(\rightarrow\)CH₃CH(OH)CN

Answer 1

The Correct Option is A

A free-radical substitution reaction is a type of reaction in which radicals replace a group in a molecule. This reaction typically involves three stages: initiation, propagation, and termination.

Let's analyze the given options to determine which one is a free-radical substitution reaction:

1. 

   
   This reaction involves the chlorination of methane (CH₄) to form chloromethane (CH₃Cl) and HCl as a by-product. This is a classic example of a free-radical substitution reaction.

2. 

   
   This reaction is an example of an electrophilic aromatic substitution, not a free-radical substitution.

3. 

   
   This reaction is an nucleophilic addition, not a free-radical substitution.
4. The reaction: CH₃CHO + HCN → CH₃CH(OH)CN is an example of a nucleophilic addition reaction, not a free-radical substitution.

Based on the analysis, the correct answer is the first option as it represents a free-radical substitution reaction where the methylene is substituted by chlorine, initiated by light (or heat).