The order of reactivities of methyl halide in the formation of Grignard reagent is

Options

A. `CH_3IgtCH_3BrgtCH_3Cl`
B. `CH_3ClgtCH_3BrgtCH_3I`
C. `CH_3BrgtCH_3ClgtCH_3I`
D. `CH_3BrgtCH_3IgtCH_3Cl`

Answer

To determine the order of reactivities of methyl halides in the formation of Grignard reagents, we need to consider the bond strengths of the carbon-halogen bonds in methyl iodide (CH3I), methyl bromide (CH3Br), and methyl chloride (CH3Cl). The reactivity of these compounds in forming Grignard reagents is inversely related to the strength of the carbon-halogen bond; weaker bonds break more easily, leading to higher reactivity.

### Step-by-Step Solution:

1. **Understanding Grignard Reagents**: Grignard reagents are formed by the reaction of alkyl halides with magnesium in dry ether. The formation involves breaking the carbon-halogen bond.

2. **Analyzing Bond Strengths**: The bond strengths of the carbon-halogen bonds in the methyl halides are as follows:
- C-I bond in CH3I is the weakest.
- C-Br bond in CH3Br is stronger than C-I but weaker than C-Cl.
- C-Cl bond in CH3Cl is the strongest.

3. **Relating Bond Strength to Reactivity**: Since the reactivity of methyl halides in forming Grignard reagents is inversely proportional to bond strength:
- CH3I (weakest bond) is the most reactive.
- CH3Br (moderate bond strength) is less reactive than CH3I but more reactive than CH3Cl.
- CH3Cl (strongest bond) is the least reactive.

4. **Establishing the Order of Reactivity**: Based on the bond strengths, we can establish the order of reactivity:
- CH3I > CH3Br > CH3Cl

5. **Conclusion**: Therefore, the correct order of reactivities of methyl halides in the formation of Grignard reagents is:
- CH3I > CH3Br > CH3Cl

### Final Answer:
The order of reactivities of methyl halides in the formation of Grignard reagent is:
**CH3I > CH3Br > CH3Cl**