A carbony compound of formula `C_(9) H_(10) O(A)`, which is a benzene derivative gives orange precipitate with 2,4-D.N.P. and also gives yellow precipitate with `I_(2)` in presence of aqueous NaOH. The total no. of isomers possible for 'A' are `"_____________"`

Answer

To solve the problem, we need to determine the total number of isomers for the carbonyl compound with the formula C₉H₁₀O, which is a benzene derivative. The compound reacts with 2,4-dinitrophenylhydrazine (2,4-DNP) to give an orange precipitate and also reacts with iodine (I₂) in the presence of aqueous NaOH to give a yellow precipitate.

### Step-by-Step Solution:

1. **Identify the Structure**:
The compound has the formula C₉H₁₀O and is a benzene derivative. This means it contains a benzene ring and a carbonyl group (C=O). The carbonyl group can either be an aldehyde or a ketone.

2. **Determine the Type of Carbonyl Compound**:
Since the compound gives a yellow precipitate with I₂ in the presence of NaOH, it indicates that the compound is likely a methyl ketone (as this reaction is characteristic of methyl ketones).

3. **Count the Carbon Atoms**:
The benzene ring consists of 6 carbon atoms, leaving us with 3 additional carbon atoms to account for in the structure.

4. **Possible Structures**:
- **Monosubstituted Benzene Derivatives**: One possible structure is having one methyl group attached to the benzene ring, making it a methyl ketone (e.g., acetophenone).
- **Disubstituted Benzene Derivatives**: Another possibility is having two substituents on the benzene ring, where one of them is a methyl group and the other is a carbonyl group (e.g., 2-methylacetophenone).

5. **Construct Isomers**:
- **Isomer 1**: Acetophenone (C₆H₅C(O)CH₃) - a methyl ketone.
- **Isomer 2**: 2-Methylacetophenone (C₆H₄(CH₃)C(O)CH₃) - a disubstituted benzene with a methyl group and a carbonyl.

6. **Confirming the Reactions**:
Both isomers will react with 2,4-DNP to form an orange precipitate and with I₂ in NaOH to form a yellow precipitate, confirming they are valid structures.

7. **Count the Total Isomers**:
After considering the structures and their reactions, we find that there are **2 isomers** possible for the compound A.

### Final Answer:
The total number of isomers possible for 'A' is **2**.

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