`R-CNoverset(H_(3)O^(+))underset("Complete hydrolysis")to Xoverset(NH_(3))underset(Delta)toYoverset((i)Br_(2)+KOH)underset((ii)H_(3)O^(+))toZ`
Identify Z.

Options

A. `R-NH_(2)`
B. `R-CH_2NH_2`
C. `R-overset(O)overset(||)C-NH_2`
D. R-CN

Answer

To solve the question step by step, we will follow the transformations outlined in the question and the video transcript.

### Step 1: Complete Hydrolysis of R-CN
We start with the compound R-CN (where R is an alkyl group and CN is the nitrile group). The first step is to perform complete hydrolysis using water (H2O) under acidic conditions (H3O+).

**Reaction:**
\[ R-CN + 2 H_2O \xrightarrow{H_3O^+} R-COOH + NH_4^+ \]

**Explanation:**
- The nitrile group (CN) is converted to a carboxylic acid (R-COOH) and ammonium ion (NH4+).
- The carbon atom in the nitrile group becomes part of the carboxylic acid.

### Step 2: Reaction with Ammonia (NH3)
Next, we take the carboxylic acid (R-COOH) and react it with ammonia (NH3) and heat it.

**Reaction:**
\[ R-COOH + NH_3 \xrightarrow{\Delta} R-CO-NH_2 \]

**Explanation:**
- The carboxylic acid reacts with ammonia to form an amide (R-CO-NH2).
- This reaction involves the formation of an ammonium salt intermediate, which upon heating gives the amide.

### Step 3: Bromination and Hydrolysis
Now, we perform the Hofmann degradation on the amide (R-CO-NH2) using bromine (Br2) and potassium hydroxide (KOH).

**Reaction:**
\[ R-CO-NH_2 + Br_2 + KOH \xrightarrow{} R-COOH + NH_2Br \]

**Explanation:**
- The amide undergoes bromination, leading to the formation of a carboxylic acid (R-COOH) and bromoamine (NH2Br).
- The reaction typically results in the loss of one carbon atom from the amide.

### Step 4: Final Hydrolysis
Finally, we perform hydrolysis on the bromoamine product.

**Reaction:**
\[ NH_2Br + H_2O \rightarrow NH_2 + HBr \]

**Explanation:**
- The bromoamine can be hydrolyzed to produce ammonia (NH2) and hydrobromic acid (HBr).
- However, the main product of interest is the carboxylic acid formed earlier.

### Conclusion: Identify Z
After performing all the steps, the final product Z is:
\[ Z = R-NH_2 + CO_2 \]

### Final Answer
Thus, the final product Z is:
\[ Z = R-NH_2 + CO_2 \]

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