In the given reaction [X] will be :
`C_(6)H_(5)-underset(O)underset(||)C-Hoverset(NH_(2)OH//H^(o+))rarr [X]`

Options

A. Mixture of syn and anti oxime
B. Only syn oxime
C. Only anti oxime
D. Reaction will not take place (NR)

Answer

To solve the question regarding the reaction of the given aldehyde with hydroxylamine (NH2OH) in the presence of an acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
The given compound is a phenyl aldehyde, specifically benzaldehyde (C6H5CHO). The other reactant is hydroxylamine (NH2OH) in acidic medium.

2. **Understand the Reaction**:
The reaction between an aldehyde and hydroxylamine leads to the formation of an oxime. In this case, the aldehyde (C6H5CHO) will react with NH2OH.

3. **Write the Reaction**:
The reaction can be represented as:
\[ C6H5CHO + NH2OH \xrightarrow{H^+} C6H5C=N-OH + H2O \]
Here, water (H2O) is eliminated in a condensation reaction.

4. **Identify the Product**:
The product formed is an oxime, which can be represented as C6H5C=N-OH. The nitrogen atom can have a lone pair of electrons, and the hydroxyl group (OH) is attached to it.

5. **Consider the Isomerism**:
The oxime can exist in two geometric forms: syn and anti. The syn form has the hydroxyl group and the phenyl group on the same side of the double bond, while the anti form has them on opposite sides.

6. **Conclusion**:
The final product [X] will be a mixture of both syn and anti isomers of the oxime.

### Final Answer:
The product [X] is a mixture of syn and anti isomers of the oxime.