Question

Which is one of the products of chlorination of methane in the presence of sunlight?

• A. DDT
• B. Chloroform
• C. Freon
• D. Alcohol

Hint:

Methane chlorination in sunlight is a continuous free-radical substitution reaction.
The possible products are chloromethane (\(\text{CH}_3\text{Cl}\)), dichloromethane (\(\text{CH}_2\text{Cl}_2\)), chloroform (\(\text{CHCl}_3\)), and carbon tetrachloride (\(\text{CCl}_4\)).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify one of the chemical products formed when methane undergoes a chlorination reaction in the presence of sunlight.

Step 2: Key Formula or Approach:
The reaction of methane with chlorine in sunlight proceeds via a free-radical chain substitution mechanism, replacing hydrogen atoms with chlorine atoms one by one.

Step 3: Detailed Explanation:

• The reaction sequence is as follows:
1. First step:
\[ \text{CH}_4 + \text{Cl}_2 \xrightarrow{h\nu} \text{CH}_3\text{Cl} + \text{HCl} \quad \text{(Chloromethane)} \] 2. Second step:
\[ \text{CH}_3\text{Cl} + \text{Cl}_2 \xrightarrow{h\nu} \text{CH}_2\text{Cl}_2 + \text{HCl} \quad \text{(Dichloromethane)} \] 3. Third step:
\[ \text{CH}_2\text{Cl}_2 + \text{Cl}_2 \xrightarrow{h\nu} \text{CHCl}_3 + \text{HCl} \quad \text{(Trichloromethane / Chloroform)} \] 4. Fourth step:
\[ \text{CHCl}_3 + \text{Cl}_2 \xrightarrow{h\nu} \text{CCl}_4 + \text{HCl} \quad \text{(Carbon tetrachloride)} \]

• The reaction typically yields a mixture of these chlorinated products depending on the concentration of chlorine.

• Chloroform (\(\text{CHCl}_3\)) is one of these standard intermediate products.


Step 4: Final Answer:
Chloroform is one of the products of the chlorination of methane.