`CH_4 + Cl_2 to CH_3 Cl + HC`, the reaction is

Options

A. addition
B. substitution
C. decomposition
D. double decomposition

Explanation

To determine the type of reaction represented by the equation \( CH_4 + Cl_2 \to CH_3Cl + HCl \), we can analyze the process step by step.

### Step 1: Identify the Reactants and Products
- The reactants in this reaction are methane (\( CH_4 \)) and chlorine gas (\( Cl_2 \)).
- The products formed are chloromethane (\( CH_3Cl \)) and hydrochloric acid (\( HCl \)).

### Step 2: Understand the Nature of the Reaction
- In this reaction, one of the hydrogen atoms in methane (\( CH_4 \)) is replaced by a chlorine atom from chlorine gas (\( Cl_2 \)).
- This results in the formation of chloromethane (\( CH_3Cl \)) and releases hydrochloric acid (\( HCl \)).

### Step 3: Classify the Reaction
- **Addition Reaction**: This involves two or more reactants combining to form a single product. This does not apply here as we have two products.
- **Substitution Reaction**: This involves one atom or group being replaced by another atom or group in a compound. This matches our reaction, where a hydrogen atom in methane is replaced by a chlorine atom.
- **Decomposition Reaction**: This involves a single compound breaking down into two or more simpler products. This does not apply here as we are not breaking down a compound.
- **Double Decomposition Reaction**: This involves two compounds reacting to form two new compounds. This does not apply here as we only have one compound changing.

### Conclusion
Based on the analysis, the reaction \( CH_4 + Cl_2 \to CH_3Cl + HCl \) is classified as a **substitution reaction**.

### Final Answer
The reaction is a **substitution reaction** (Option B).

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