`R - CN overset((i) DIBAL - H ) underset((ii)H _(2) O )to R - Y`
Consider the above reaction and identify `Y`

Options

A. `-CH_(2) NH _(2)`
B. `-CONH_(2)`
C. `-CHO`
D. `-COOH`

Answer

To solve the problem, we need to analyze the reaction step by step, starting from the alkyl cyanide (R-CN) and determining what Y is after the reaction with DIBAL-H followed by hydrolysis.

### Step-by-Step Solution:

1. **Identify the Starting Material**:
The starting material is an alkyl cyanide, represented as R-CN. The cyanide group (CN) consists of a carbon triple-bonded to a nitrogen atom.

2. **Reaction with DIBAL-H**:
DIBAL-H (Diisobutylaluminium hydride) is a reducing agent that can reduce nitriles (CN) to imines. During this reaction, the CN group will be reduced to form an intermediate imine (R-CH=NH-Al(i-Bu)2).

- The nitrogen in the CN group donates its lone pair to bond with aluminum, forming a complex.
- The carbon atom in the cyanide group becomes electron-deficient and forms a double bond with nitrogen while breaking the triple bond.

3. **Formation of Imine**:
The reaction results in the formation of an imine (R-CH=NH) where the nitrogen is now bonded to aluminum and has a positive charge due to the electron donation.

4. **Hydrolysis of the Imine**:
The next step involves hydrolysis, where water (H2O) is added. The imine undergoes hydrolysis to form an aldehyde.

- The double bond between carbon and nitrogen breaks, allowing the carbon to bond with an oxygen atom from water.
- This results in the formation of an aldehyde (R-CHO), where the nitrogen is replaced by an oxygen atom.

5. **Identify Y**:
After the hydrolysis, the product formed is R-CHO. Hence, Y in the reaction is the aldehyde group (CHO).

### Final Answer:
Thus, Y is identified as CHO.