The compound (C) in the given sequence of reaction is ,
`C_6H_5OHoverset(NaOH)rarr(A)overset(CO_2)rarr(B)overset(HCl)rarr(C)`

Options

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

Answer

To determine the compound (C) in the given sequence of reactions, we will analyze each step carefully.

### Step 1: Identify the starting compound
The starting compound is phenol, which has the molecular formula \( C_6H_5OH \).

### Step 2: Reaction with Sodium Hydroxide (NaOH)
Phenol is acidic and reacts with sodium hydroxide (NaOH) to form sodium phenoxide. The reaction can be represented as:
\[ C_6H_5OH + NaOH \rightarrow C_6H_5O^{-}Na^{+} + H_2O \]
Here, \( A \) is sodium phenoxide (\( C_6H_5O^{-}Na^{+} \)).

### Step 3: Reaction with Carbon Dioxide (CO2)
Next, sodium phenoxide reacts with carbon dioxide (CO2). The phenoxide ion acts as a nucleophile and attacks the electrophilic carbon in CO2. The reaction can be represented as:
\[ C_6H_5O^{-} + CO_2 \rightarrow C_6H_4(OH)(COO^{-}) \]
This results in the formation of a carboxylate ion, which is a carboxylic acid derivative. The intermediate formed is a carboxylate ion, which can be represented as \( C_6H_4(OH)(COO^{-}) \).

### Step 4: Protonation with HCl
The carboxylate ion formed in the previous step can then react with hydrochloric acid (HCl). The carboxylate ion will accept a proton (H+) from HCl, leading to the formation of a carboxylic acid. The reaction can be represented as:
\[ C_6H_4(OH)(COO^{-}) + HCl \rightarrow C_6H_4(OH)(COOH) + Cl^{-} \]
This results in the formation of salicylic acid (\( C_6H_4(OH)(COOH) \)), which is compound \( C \).

### Final Answer
Thus, the compound \( C \) in the given sequence of reactions is **salicylic acid**.