Which one of the following will result in the formation of an ether?

Options

A. `(CH_(3))_(3)Coverset(-)Ooverset(+)Na+ CH_(3)CH_(2)Brrarr`
B. `(CH_(3))_(3)CBr+C_(2)H_(5)overset(-)Ooverset(+)Nararr`
C. `C_(6)H_(5)ONa+CH_(3)Brrarr`
D. `C_(6)H_(5)Br+CH_(3)O^(-)overset(+)Nararr`

Answer

To determine which reaction will result in the formation of an ether, we need to analyze the given reactions one by one.

### Step-by-Step Solution:

1. **Identify the Reactions**:
We have four reactions involving different alkyl halides and sodium alkoxide. The general reaction for ether formation is through the Williamson ether synthesis, which involves the reaction of an alkoxide ion with an alkyl halide.

2. **First Reaction**:
- Reactants: CH3O−Na+ (sodium alkoxide) and CH3CH2Br (ethyl bromide).
- Mechanism: The alkoxide ion acts as a nucleophile and attacks the electrophilic carbon in the alkyl halide (CH3CH2Br) through an SN2 mechanism.
- Product: This reaction will yield CH3CH2OCH3 (ethyl methyl ether).
- Conclusion: This reaction results in the formation of an ether.

3. **Second Reaction**:
- Reactants: CH3O−Na+ and a tertiary alkyl halide.
- Mechanism: Tertiary alkyl halides do not undergo SN2 reactions due to steric hindrance; they typically undergo elimination reactions instead.
- Conclusion: This reaction will not result in the formation of an ether.

4. **Third Reaction**:
- Reactants: C6H5O−Na+ (sodium phenoxide) and CH3Br (methyl bromide).
- Mechanism: The phenoxide ion acts as a nucleophile and attacks the methyl halide through an SN2 mechanism.
- Product: This reaction will yield anisole (C6H5OCH3), which is an ether.
- Conclusion: This reaction results in the formation of an ether.

5. **Fourth Reaction**:
- Reactants: C6H5Br (bromobenzene) and sodium alkoxide.
- Mechanism: Aryl halides like bromobenzene are less reactive towards nucleophilic substitution due to resonance stabilization and steric hindrance.
- Conclusion: This reaction will not result in the formation of an ether.

### Final Answer:
The reactions that result in the formation of an ether are the **first reaction** (CH3O−Na+ + CH3CH2Br) and the **third reaction** (C6H5O−Na+ + CH3Br).