`CH_3CH_2Cloverset(NaCN)rarrXoverset(Ni//H_2)rarrY`
`Yoverset(Acetic)underset(anhydride)rarrZ`
Z in the above reaction sequence is

Options

A. `CH_3CH_2CH_2NHCOCH_3`
B. `CH_3CH_2CH_2NH_2`
C. `CH_3CH_2CH_2CONHCH_3`
D. `CH_3CH_2CH_2CONHCOCH_3`

Explanation

To solve the problem given in the question, we will follow the sequence of reactions step by step.

### Step 1: Formation of Compound X
The first reaction is:
\[ \text{CH}_3\text{CH}_2\text{Cl} + \text{NaCN} \rightarrow X \]

- **Explanation**: Here, we have ethyl chloride (CH3CH2Cl) reacting with sodium cyanide (NaCN). Sodium cyanide provides the cyanide ion (CN⁻), which acts as a nucleophile. The cyanide ion attacks the electrophilic carbon atom in the ethyl chloride, leading to the substitution of the chlorine atom (Cl) with the cyanide group (CN).

- **Result**: The product formed is:
\[ X = \text{CH}_3\text{CH}_2\text{CN} \]

### Step 2: Formation of Compound Y
The next reaction is:
\[ X + \text{H}_2/\text{Ni} \rightarrow Y \]

- **Explanation**: In this step, the compound X (CH3CH2CN) is subjected to hydrogenation using hydrogen gas (H2) in the presence of a nickel catalyst. This reaction reduces the nitrile group (CN) to an amine (NH2). The carbon chain remains the same while the CN group is converted to CH2NH2.

- **Result**: The product formed is:
\[ Y = \text{CH}_3\text{CH}_2\text{CH}_2\text{NH}_2 \]

### Step 3: Formation of Compound Z
The final reaction is:
\[ Y + \text{Acetic Anhydride} \rightarrow Z \]

- **Explanation**: In this step, the amine (Y) reacts with acetic anhydride. The acetic anhydride acts as an electrophile and reacts with the amine group (NH2) to form an amide. The nitrogen atom in the amine attacks the carbonyl carbon of the acetic anhydride, leading to the formation of a new bond and the release of acetic acid.

- **Result**: The product formed is:
\[ Z = \text{CH}_3\text{CH}_2\text{CH}_2\text{NHCOCH}_3 \]

### Final Answer
The final compound Z is:
\[ Z = \text{CH}_3\text{CH}_2\text{CH}_2\text{NHCOCH}_3 \]