Which of the following pairs will not form ether?

Options

A. `C_(2) H_(5) Br+C_(2) H_(5) ONa`
B. `C_(2) H_(5)Br+C_(6)H_(5) ONa`
C. `C_(2)H_(5)Br+(CH_(3))_(3)CONa`
D. `C_(6)H_(5)Br+CH_(3)COONa`

Answer

To determine which of the given pairs will not form an ether, we need to analyze the reactions of each pair. An ether is formed when an alkyl or aryl group is bonded to an oxygen atom. Let's go through the options step by step.

### Step-by-Step Solution:

1. **Understanding Ether Formation**:
- Ethers are formed when an alkoxide ion (R-O^-) reacts with an alkyl halide (R'-X) where X is a halogen (like Br).
- The alkoxide ion acts as a nucleophile and attacks the electrophilic carbon of the alkyl halide, resulting in the formation of an ether (R-O-R').

2. **Analyzing the First Pair (C2H5O^- + C2H5Br)**:
- Here, the alkoxide ion is C2H5O^-. The alkyl halide is C2H5Br.
- The oxygen will attack the carbon bonded to bromine, leading to the formation of an ether (C2H5-O-C2H5).
- **Conclusion**: This pair will form an ether.

3. **Analyzing the Second Pair (C6H5O^- + C2H5Br)**:
- The alkoxide ion is C6H5O^-. The alkyl halide is C2H5Br.
- The oxygen will attack the carbon of C2H5Br, resulting in the formation of an ether (C6H5-O-C2H5).
- **Conclusion**: This pair will also form an ether.

4. **Analyzing the Third Pair (C2H5Br + CH3O^-)**:
- The alkoxide ion is CH3O^-. The alkyl halide is C2H5Br.
- The oxygen will attack the carbon of C2H5Br, leading to the formation of an ether (CH3-O-C2H5).
- **Conclusion**: This pair will form an ether as well.

5. **Analyzing the Fourth Pair (C6H5Br + CH3C(=O)O^-)**:
- Here, we have C6H5Br as the alkyl halide and CH3C(=O)O^- (which is an acetate ion).
- The acetate ion will not act as a nucleophile to form an ether; instead, it will react with the bromine to form an ester (C6H5-O-C(=O)CH3).
- **Conclusion**: This pair will NOT form an ether; it will form an ester instead.

### Final Answer:
The pair that will not form an ether is **C6H5Br + CH3C(=O)O^-**.