Z' in the following sequence of reaction is `C_6 H_6 overset(HNO_3 // H_2 SO_4) underset(Delta) to W overset(Zn//HCl) to X overset(NaNO_2) underset(HCl, 0-5^@C) to Y overset(H_2 O//H_3 PO_2) to Z`

Options

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B.
C.
D.

Explanation

To solve the problem step by step, we will analyze each reaction in the sequence provided and determine the final product Z.

### Step 1: Nitration of Benzene
- **Reaction**: \( C_6H_6 \overset{HNO_3}{\underset{H_2SO_4}{\Delta}} \)
- **Process**: Benzene reacts with a mixture of nitric acid (HNO₃) and sulfuric acid (H₂SO₄) to undergo nitration. The electrophile generated in this reaction is the nitronium ion (NO₂⁺).
- **Product W**: The product formed is nitrobenzene (\( C_6H_5NO_2 \)).

### Step 2: Reduction of Nitrobenzene
- **Reaction**: \( W \overset{Zn/HCl}{\rightarrow} \)
- **Process**: Nitrobenzene undergoes reduction when treated with zinc (Zn) and hydrochloric acid (HCl). The nitro group (–NO₂) is reduced to an amino group (–NH₂).
- **Product X**: The product formed is aniline (\( C_6H_5NH_2 \)).

### Step 3: Diazotization of Aniline
- **Reaction**: \( X \overset{NaNO_2}{\underset{HCl, 0-5^\circ C}{\rightarrow}} \)
- **Process**: Aniline reacts with sodium nitrite (NaNO₂) in the presence of hydrochloric acid (HCl) at low temperatures (0-5°C). This reaction forms diazonium salt.
- **Product Y**: The product formed is benzene diazonium chloride (\( C_6H_5N_2Cl \)).

### Step 4: Hydrolysis of Benzene Diazonium Chloride
- **Reaction**: \( Y \overset{H_2O/H_3PO_2}{\rightarrow} \)
- **Process**: Benzene diazonium chloride undergoes hydrolysis when treated with water and phosphorous acid (H₃PO₂). The diazonium group (–N₂⁺) is replaced by a hydrogen atom (–H).
- **Product Z**: The final product formed is benzene (\( C_6H_6 \)).

### Final Answer
Thus, the final product Z in the sequence of reactions is benzene (\( C_6H_6 \)).

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