How will you convert benzene into
(i) p-nitrobromobenzene
(ii) m-nitrochlorobenzene
(iii) p -nitrotoluene
(iv) acetophenone

Explanation

To convert benzene into the specified compounds, we will follow a series of chemical reactions. Here’s a step-by-step breakdown for each conversion:

### (i) Conversion of Benzene to p-Nitrobromobenzene

1. **Bromination of Benzene**:
- React benzene (C6H6) with bromine (Br2) in the presence of anhydrous FeBr3 as a catalyst.
- This will produce bromobenzene (C6H5Br).

**Reaction**:
\[ C_6H_6 + Br_2 \xrightarrow{FeBr_3} C_6H_5Br \]

2. **Nitration of Bromobenzene**:
- Next, perform nitration by reacting bromobenzene with concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).
- This will introduce a nitro group (NO2) at the para position relative to the bromine atom, yielding p-nitrobromobenzene (C6H4BrNO2).

**Reaction**:
\[ C_6H_5Br + HNO_3 + H_2SO_4 \rightarrow C_6H_4BrNO_2 + H_2O \]

3. **Separation**:
- Since both ortho and para products are formed, use fractional distillation to separate the desired p-nitrobromobenzene from the ortho product.

### (ii) Conversion of Benzene to m-Nitrochlorobenzene

1. **Nitration of Benzene**:
- Start with benzene and perform nitration using concentrated HNO3 and H2SO4 to form nitrobenzene (C6H5NO2).

**Reaction**:
\[ C_6H_6 + HNO_3 + H_2SO_4 \rightarrow C_6H_5NO_2 + H_2O \]

2. **Chlorination of Nitrobenzene**:
- Now, chlorinate nitrobenzene using chlorine (Cl2) in the presence of anhydrous AlCl3.
- The nitro group directs the chlorine to the meta position, yielding m-nitrochlorobenzene (C6H4ClNO2).

**Reaction**:
\[ C_6H_5NO_2 + Cl_2 \xrightarrow{AlCl_3} C_6H_4ClNO_2 + HCl \]

### (iii) Conversion of Benzene to p-Nitrotoluene

1. **Friedel-Crafts Alkylation**:
- React benzene with methyl chloride (CH3Cl) in the presence of anhydrous AlCl3 to form toluene (C6H5CH3).

**Reaction**:
\[ C_6H_6 + CH_3Cl \xrightarrow{AlCl_3} C_6H_5CH_3 + HCl \]

2. **Nitration of Toluene**:
- Perform nitration on toluene using concentrated HNO3 and H2SO4.
- This will produce both ortho and para nitrotoluene, but we are interested in the para product.

**Reaction**:
\[ C_6H_5CH_3 + HNO_3 + H_2SO_4 \rightarrow C_6H_4(CH_3)(NO_2) + H_2O \]

3. **Separation**:
- Use fractional distillation to isolate the desired p-nitrotoluene from the ortho product.

### (iv) Conversion of Benzene to Acetophenone

1. **Friedel-Crafts Acylation**:
- React benzene with acetyl chloride (CH3COCl) in the presence of anhydrous AlCl3 to form acetophenone (C6H5COCH3).

**Reaction**:
\[ C_6H_6 + CH_3COCl \xrightarrow{AlCl_3} C_6H_5COCH_3 + HCl \]

### Summary of Conversions:
1. Benzene → p-Nitrobromobenzene: Bromination → Nitration → Fractional Distillation
2. Benzene → m-Nitrochlorobenzene: Nitration → Chlorination
3. Benzene → p-Nitrotoluene: Friedel-Crafts Alkylation → Nitration → Fractional Distillation
4. Benzene → Acetophenone: Friedel-Crafts Acylation

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