Which of the following halides does form `G.R` when treated with magnesium in the presence of ether ?

Options

A. `PhBr`
B.
C.
D.

Explanation

To determine which halides form Grignard reagents when treated with magnesium in the presence of ether, we need to analyze each option based on the presence of active hydrogen atoms. Grignard reagents are formed from alkyl or aryl halides that do not contain acidic hydrogens.

### Step-by-Step Solution:

1. **Understanding Grignard Reagents:**
- Grignard reagents are organometallic compounds represented as R-MgX, where R is an alkyl or aryl group, and X is a halogen.
- They are formed when alkyl or aryl halides react with magnesium in the presence of an ether solvent.

2. **Identifying Active Hydrogen:**
- Active hydrogens are typically found in compounds such as alcohols, amines, and carboxylic acids. These hydrogens can interfere with the formation of Grignard reagents.

3. **Analyzing Each Option:**
- **Option A: Phenyl Bromide (C6H5Br)**
- This compound does not have any active hydrogen atoms. Therefore, it can react with magnesium to form a Grignard reagent (C6H5-MgBr).

- **Option B: Alkyl Halide (e.g., 1-Bromopropane)**
- Similar to phenyl bromide, this compound does not have active hydrogen atoms. It can also react with magnesium to form a Grignard reagent (C3H7-MgBr).

- **Option C: Another Alkyl Halide (e.g., 1-Bromo-2-methylpropane)**
- This compound also lacks active hydrogen atoms, allowing it to form a Grignard reagent (C4H9-MgBr).

- **Option D: Parabromoaniline (C6H4BrNH2)**
- This compound contains an amine group (NH2), which has an active hydrogen. When reacted with magnesium, the active hydrogen will interfere with the formation of the Grignard reagent, leading to the formation of an unstable compound instead.

4. **Conclusion:**
- Options A, B, and C can form Grignard reagents, while option D cannot due to the presence of active hydrogen.

### Final Answer:
**Options A, B, and C form Grignard reagents when treated with magnesium in the presence of ether. Option D does not form Grignard reagent.**

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