Identify the product 'Z' in the following sequence of reactions.
`CH_(3)CNoverset(Na+C_(2)H_(5)OH)rarr Xoverset(HNO_(2))underset(H_(2)O)rarrYoverset(K_(2)Cr_(2)O_(7))underset(H_(2)SO_(4))rarr Z`

Options

A. `CH_(3)CHO`
B. `CH_(3)CONH_(2)`
C. `CH_(3)COOH`
D. `CH_(3)CH_(2)NHOH`

Answer

To identify the product 'Z' in the given sequence of reactions, we will analyze each step systematically.

### Step 1: Identify the starting compound
The starting compound is **CH₃CN** (acetonitrile).

### Step 2: First reaction with sodium in ethanol
When acetonitrile (CH₃CN) is treated with sodium (Na) in ethanol (C₂H₅OH), it acts as a strong reducing agent. This reaction reduces the nitrile group (CN) to a primary amine.

**Product X:** The primary amine formed is **CH₃CH₂NH₂** (ethylamine).

### Step 3: Second reaction with nitrous acid (HNO₂)
The primary amine (X) is then treated with nitrous acid (HNO₂). This reaction leads to the formation of a diazonium salt, which is unstable in this case and decomposes to release nitrogen gas (N₂).

**Product Y:** The product formed is **CH₃CH₂OH** (ethanol) and nitrogen gas is released.

### Step 4: Third reaction with potassium dichromate (K₂Cr₂O₇) in sulfuric acid (H₂SO₄)
The final step involves the oxidation of ethanol (Y) using potassium dichromate (K₂Cr₂O₇) in the presence of sulfuric acid (H₂SO₄). K₂Cr₂O₇ is a strong oxidizing agent, and it will oxidize ethanol to acetic acid.

**Product Z:** The final product is **CH₃COOH** (acetic acid).

### Summary of the Reaction Sequence
1. **CH₃CN + Na/C₂H₅OH → CH₃CH₂NH₂ (X)**
2. **CH₃CH₂NH₂ + HNO₂ → CH₃CH₂OH (Y) + N₂ (gas)**
3. **CH₃CH₂OH + K₂Cr₂O₇/H₂SO₄ → CH₃COOH (Z)**

### Final Answer
The product 'Z' is **CH₃COOH** (acetic acid).

---