Which metal is used in the preparation of Grignard's reagents from alkyl halides ?

Explanation

To answer the question of which metal is used in the preparation of Grignard's reagents from alkyl halides, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Grignard Reagents**: Grignard reagents are organomagnesium compounds typically represented as R-Mg-X, where R is an alkyl or aryl group, and X is a halogen (like Cl, Br, or I).

2. **Identifying the Reaction**: The preparation of Grignard reagents involves the reaction of alkyl halides with a metal. The general reaction can be written as:
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