In the given reaction sequence
`C_(6)H_(5)CHO+CH_(3)-NO_(2)overset((i)NaOH(ii)Delta)rarr[X]`
[X] will be

Options

A. `C_(6)H_(5)-CHOH-CH_(2)-CHO`
B. `C_(6)H_(5)CH_(2)OH`
C. `C_(6)H_(5)-COOH`
D. `C_(6)H_(5)-CH=CH-NO_(2)`

Answer

To solve the problem, we need to analyze the reaction between benzaldehyde (C₆H₅CHO) and nitromethane (CH₃NO₂) in the presence of sodium hydroxide (NaOH) and heat.

### Step-by-Step Solution:

1. **Identify the Reactants**:
- We have benzaldehyde (C₆H₅CHO) and nitromethane (CH₃NO₂).

2. **Understand the Role of Sodium Hydroxide**:
- Sodium hydroxide acts as a base in this reaction. It will deprotonate the nitromethane, which has an acidic hydrogen on the carbon adjacent to the nitro group.

3. **Deprotonation of Nitromethane**:
- The hydroxide ion (OH⁻) from NaOH abstracts the acidic hydrogen from nitromethane (CH₃NO₂), forming a nitronate ion (CH₂NO₂⁻).

4. **Nucleophilic Addition**:
- The nitronate ion (CH₂NO₂⁻) acts as a nucleophile and attacks the carbonyl carbon of benzaldehyde (C₆H₅CHO). This results in the formation of a new intermediate.

5. **Formation of the Intermediate**:
- The intermediate formed can be represented as C₆H₅C(OH)(CH₂NO₂). This intermediate has a hydroxyl group (OH) and the nitro group (NO₂) attached to the same carbon.

6. **Protonation**:
- The intermediate can then undergo protonation to form a more stable compound, which is C₆H₅C(CH₂NO₂)(OH).

7. **Heating and Elimination of Water**:
- Upon heating, this compound can undergo dehydration (loss of water) to form an α,β-unsaturated carbonyl compound. The final product will be C₆H₅C=CHNO₂.

8. **Final Product**:
- The final product [X] is thus C₆H₅C=CHNO₂, which is the compound formed after the aldol condensation-like reaction and subsequent dehydration.

### Conclusion:
The product [X] formed in the reaction sequence is C₆H₅C=CHNO₂.