An aromatic compound 'X' `(C_9H_8O_3)` turns blue litmus to red.It gives yellow precipitate with `I_2//NaOH` and forms Y `(C_8H_5O_4)`. Y forms three mononitro isomeric products. Identify X.

Options

A.
B.
C.
D. None of these

Answer

To identify the aromatic compound 'X' with the molecular formula \( C_9H_8O_3 \), we can follow these steps:

### Step 1: Analyze the Molecular Formula
The molecular formula \( C_9H_8O_3 \) indicates that the compound is likely aromatic due to the presence of a benzene ring. The degree of unsaturation can be calculated, which suggests that there are multiple rings or double bonds.

**Hint:** Look for the presence of a benzene ring in the structure.

### Step 2: Identify Functional Groups
The problem states that 'X' turns blue litmus paper red, indicating that it is acidic. This suggests the presence of a carboxylic acid group (-COOH) in the structure.

**Hint:** Remember that only acidic compounds can turn blue litmus red.

### Step 3: Iodoform Test
The compound gives a yellow precipitate with iodine and sodium hydroxide (NaOH), which is characteristic of the iodoform test. This test indicates the presence of a methyl ketone (R-CO-CH3) or a secondary alcohol adjacent to a methyl group.

**Hint:** The iodoform test is a key indicator of specific functional groups.

### Step 4: Construct Possible Structures
Considering the above points, we can deduce that 'X' must contain:
- A benzene ring
- A carboxylic acid group (-COOH)
- A methyl group attached to a carbonyl (ketone) or a secondary alcohol.

This leads us to propose a structure like:
- \( C_6H_4(COOH)(COCH_3) \)

**Hint:** Combine the functional groups logically to form a stable aromatic compound.

### Step 5: Verify the Structure
The proposed structure must satisfy the molecular formula \( C_9H_8O_3 \):
- 6 carbons from the benzene ring
- 1 carbon from the carboxylic acid
- 2 carbons from the methyl ketone

This gives a total of 9 carbons, which matches the formula.

### Step 6: Identify Compound Y
When 'X' reacts with iodine and NaOH, it forms 'Y' with the formula \( C_8H_5O_4 \). This suggests that one of the substituents is removed or transformed during the reaction.

**Hint:** Keep track of how the reaction alters the structure.

### Step 7: Nitration of Compound Y
The problem states that 'Y' can form three mononitro isomers upon nitration. The positions of the substituents on the benzene ring will determine the possible positions for the nitro group.

**Hint:** Consider ortho and para positions for the nitro group relative to the existing substituents.

### Step 8: Conclusion
After analyzing all the steps, we conclude that the structure of 'X' is likely:
- **X = 4-hydroxy-3-methylbenzoic acid (or p-hydroxy-methylbenzoic acid)**

Thus, the final identification of compound 'X' is:

**Answer:** \( C_6H_4(COOH)(COCH_3) \) or specifically, 4-hydroxy-3-methylbenzoic acid.