When sodium or potassium phenoxide is heated with carbon dioxide, followed by acidification, we get

Options

A. Salicylic acid
B. Salicyladehyde
C. Benzoic acid
D. Cinnamic acid

Explanation

To solve the question regarding the reaction of sodium or potassium phenoxide with carbon dioxide followed by acidification, we can break down the process into clear steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactant is sodium phenoxide (C6H5O-Na+). It consists of a phenyl group (C6H5) attached to a sodium ion through an oxygen atom.

2. **Reaction with Carbon Dioxide**:
- When sodium phenoxide is heated with carbon dioxide (CO2), a carboxylation reaction occurs. The carbon dioxide reacts with the phenoxide ion to form a carboxylate ion.
- The reaction can be represented as:
\[ C6H5O^- + CO2 \rightarrow C6H4(OH)(COO^-) \]
- In this step, the carbon dioxide adds to the ortho or para position of the phenoxide ion, leading to the formation of sodium salicylate (C6H4(OH)(COO^-)).

3. **Acidification**:
- The next step involves acidifying the reaction mixture. This is typically done by adding a strong acid, such as hydrochloric acid (HCl) or hydronium ion (H3O+).
- The sodium salicylate formed in the previous step reacts with the acid, replacing the sodium ion with a hydrogen ion:
\[ C6H4(OH)(COO^-) + H3O^+ \rightarrow C6H4(OH)(COOH) + Na^+ \]
- This results in the formation of salicylic acid (C6H4(OH)(COOH)), which has both a hydroxyl group (–OH) and a carboxylic acid group (–COOH) on the benzene ring.

4. **Final Product**:
- The final product of this reaction is salicylic acid (C7H6O3), which is a compound known for its use in the production of aspirin and as a topical anti-inflammatory agent.

### Conclusion:
Thus, when sodium or potassium phenoxide is heated with carbon dioxide and then acidified, the product obtained is **salicylic acid**.