Toluene is nitrated and the resulting product is reduced with tin and hydrochloric acid. The product so obtained is diazotised and then heated with cuprous bromide. The reaction mixture so formed contains -

Options

A. mixture of o– and p-dibromobenzenes
B. mixture of o- and p-bromoanilines
C. mixture of o- and m-bromotoluenes
D. mixture of o- and p-bromotoluenes

Answer

To solve the problem step by step, let's break down the reactions involved when toluene is nitrated, reduced, diazotized, and then treated with cuprous bromide.

### Step 1: Nitration of Toluene
- **Reaction**: Toluene (C6H5CH3) is treated with a nitrating mixture (HNO3 and H2SO4).
- **Products**: The electrophile generated is the nitronium ion (NO2+). Due to the ortho-para directing effect of the methyl group (CH3), both ortho and para nitrotoluene will be formed.

**Hint**: Remember that toluene has a methyl group which directs electrophilic substitution to the ortho and para positions.

### Step 2: Reduction of Nitro Compounds
- **Reaction**: The nitrotoluene products (ortho and para) are then reduced using tin (Sn) and hydrochloric acid (HCl).
- **Products**: This reduction converts the nitro group (NO2) into an amino group (NH2), resulting in ortho and para toluidine (C6H4(NH2)CH3).

**Hint**: The reduction of nitro groups to amino groups is a common reaction in organic chemistry.

### Step 3: Diazotization
- **Reaction**: The resulting toluidine is diazotized using sodium nitrite (NaNO2) and hydrochloric acid (HCl) at low temperatures (0-5°C).
- **Products**: This reaction converts the amino group (NH2) into a diazonium salt (C6H4(N2+)CH3).

**Hint**: Diazotization typically occurs at low temperatures to stabilize the diazonium salt.

### Step 4: Reaction with Cuprous Bromide
- **Reaction**: The diazonium salt is then treated with cuprous bromide (CuBr).
- **Products**: This reaction replaces the diazonium group with a bromine atom, resulting in bromotoluene (C6H4BrCH3). The reaction can yield both ortho and para bromotoluene depending on the starting material.

**Hint**: The reaction with cuprous bromide is known as the Gattermann reaction, which introduces bromine into the aromatic ring.

### Final Products
The final reaction mixture contains ortho-bromotoluene and para-bromotoluene.

### Summary of the Reaction Sequence
1. **Nitration**: Toluene → Ortho-nitrotoluene + Para-nitrotoluene
2. **Reduction**: Ortho-nitrotoluene + Para-nitrotoluene → Ortho-toluidine + Para-toluidine
3. **Diazotization**: Ortho-toluidine + Para-toluidine → Ortho-diazotoluene + Para-diazotoluene
4. **Gattermann Reaction**: Ortho-diazotoluene + Para-diazotoluene → Ortho-bromotoluene + Para-bromotoluene

### Conclusion
The reaction mixture contains ortho-bromotoluene and para-bromotoluene.

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