The reaction sequence
`C_(6)H_(5)-CH=CH-Choverset([X])rarr C_(6)H_(5)-CH_(2)-CH_(2)-CH_(2)OH`
[X] will be

Options

A. `LiAlH_(4)`
B. `NaBH_(4)`
C. Aluminium isopropoxide
D. All of these

Answer

To solve the problem, we need to determine the reagent [X] that can convert the compound \( C_6H_5-CH=CH-CHO \) into \( C_6H_5-CH_2-CH_2-CH_2OH \).

### Step-by-Step Solution:

1. **Identify the Starting Material**:
The starting material is \( C_6H_5-CH=CH-CHO \). This compound has a phenyl group (benzene ring) attached to a carbon-carbon double bond (alkene) and an aldehyde group (CHO).

2. **Identify the Desired Product**:
The desired product is \( C_6H_5-CH_2-CH_2-CH_2OH \). This product has a phenyl group attached to a straight-chain alkane with a terminal alcohol group (OH).

3. **Determine the Reaction Type**:
The transformation involves the reduction of both the carbon-carbon double bond and the aldehyde group. The aldehyde group needs to be converted into an alcohol, and the double bond needs to be fully saturated.

4. **Select the Appropriate Reagent**:
- **Lithium Aluminum Hydride (LiAlH_4)**: This is a strong reducing agent that can reduce aldehydes to alcohols and can also reduce alkenes to alkanes.
- **Sodium Borohydride (NaBH_4)**: This reagent is milder and primarily reduces aldehydes and ketones, but it does not reduce alkenes.
- **Aluminum Isopropoxide**: This reagent is not typically used for such reductions.

5. **Apply the Reagent**:
Using Lithium Aluminum Hydride (LiAlH_4) on the starting material \( C_6H_5-CH=CH-CHO \) will:
- Reduce the aldehyde (CHO) to an alcohol (CH2OH).
- Reduce the double bond (C=C) to a single bond (C-C), resulting in the formation of the desired product \( C_6H_5-CH_2-CH_2-CH_2OH \).

6. **Conclusion**:
Therefore, the reagent [X] that will convert \( C_6H_5-CH=CH-CHO \) to \( C_6H_5-CH_2-CH_2-CH_2OH \) is **Lithium Aluminum Hydride (LiAlH_4)**.

### Final Answer:
**[X] is Lithium Aluminum Hydride (LiAlH_4)**.

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