The increasing order of reduction of alkyl halides with zinc and dilute HCl is

Options

A. `R - Cl lt R - I lt R - Br`
B. `R - Cl lt R - Br lt R - I`
C. `R - I lt R - Br lt R Cl`
D. `R - Br lt R - I lt R - Cl`

Explanation

To determine the increasing order of reduction of alkyl halides with zinc and dilute HCl, we need to analyze the stability of the halide ions produced during the reaction. The halides we will consider are Cl⁻, Br⁻, and I⁻.

### Step-by-Step Solution:

1. **Identify the Reaction**:
The reaction involves alkyl halides (RX) being reduced to alkanes (RH) in the presence of zinc and dilute HCl. The halogen (X) is replaced by hydrogen (H) during this reduction process.

2. **Understand the Role of Halide Ions**:
During the reduction, the halide ion (X⁻) is formed. The stability of this halide ion is crucial because a more stable halide ion will lead to a faster reduction reaction.

3. **Stability of Halide Ions**:
The stability of halide ions generally increases down the group in the periodic table. The trend for halides is:
- Iodide (I⁻) > Bromide (Br⁻) > Chloride (Cl⁻)
This is because larger atoms can better stabilize the negative charge due to their larger size and ability to diffuse the charge over a greater volume.

4. **Order of Reduction**:
Since the stability of the halide ions is directly related to the rate of reduction, we can establish the following order:
- Cl⁻ is the least stable, leading to the slowest reduction.
- Br⁻ is more stable than Cl⁻ but less stable than I⁻, leading to a moderate reduction rate.
- I⁻ is the most stable, leading to the fastest reduction.

5. **Conclusion**:
Therefore, the increasing order of reduction of alkyl halides with zinc and dilute HCl is:
- RCl < RBr < RI

### Final Answer:
The increasing order of reduction of alkyl halides with zinc and dilute HCl is:
**RCl < RBr < RI**

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