In the reaction `Ar - OH +RX overset ("Alkali") to A ` . A is :

Options

A. An aldehyde
B. An aryl chloride
C. An ether
D. A ketone

Answer

To solve the question regarding the reaction of phenol with RX in the presence of an alkali to form compound A, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants are phenol (Ar-OH) and RX, where R is an alkyl group and X is a halogen.

2. **Understanding the Reaction Conditions**:
- The reaction occurs in the presence of an alkali, which is a strong base. This base will deprotonate the phenol.

3. **Formation of Phenoxide Ion**:
- Phenol (Ar-OH) can lose a proton (H⁺) to form the phenoxide ion (Ar-O⁻). This occurs because the oxygen atom in the hydroxyl group is more electronegative than hydrogen, making the O-H bond polar and allowing for the release of H⁺.

4. **Formation of Carbocation**:
- The RX compound undergoes a reaction where the halogen (X) leaves, forming a carbocation (R⁺). This is possible because halogens are good leaving groups due to their electronegativity.

5. **Nucleophilic Attack**:
- The phenoxide ion (Ar-O⁻), which is now a strong nucleophile, attacks the electron-deficient carbocation (R⁺).

6. **Formation of Ether**:
- The result of this nucleophilic attack is the formation of an ether (Ar-O-R), where the oxygen atom is bonded to both the aromatic group (Ar) and the alkyl group (R).

7. **Conclusion**:
- Therefore, compound A formed in the reaction is an ether, specifically an aryl ether.

### Final Answer:
A is an ether (Ar-O-R).

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