In which of the reaction formation of Diazonium salt takes place ?

Options

A.
B.
C.
D.

Answer

To determine in which reaction the formation of diazonium salts takes place, we need to follow these steps:

### Step 1: Understand the formation of diazonium salts
Diazonium salts are typically formed from primary aromatic amines when they react with nitrous acid (HNO2), which is generated in situ from sodium nitrite (NaNO2) and a mineral acid like hydrochloric acid (HCl).

### Step 2: Identify the reactants
The general reaction for the formation of diazonium salts can be represented as follows:
- **Reactants**: Primary aromatic amine (ArNH2) + NaNO2 + HCl
- **Conditions**: The reaction is carried out at low temperatures (273-278 K) to prevent decomposition of the diazonium salt.

### Step 3: Write the reaction
The reaction can be summarized as:
\[ \text{ArNH}_2 + \text{NaNO}_2 + \text{HCl} \rightarrow \text{ArN}_2^+ \text{Cl}^- + \text{NaCl} + \text{H}_2\text{O} \]
Here, ArN2+ is the diazonium salt formed.

### Step 4: Analyze the options
1. **Option 1**: Primary amine with NaNO2 and HCl - This is correct as it leads to the formation of diazonium salts.
2. **Option 2**: Secondary amine - This is incorrect as secondary amines do not form diazonium salts.
3. **Option 3**: Tertiary amine - This is also incorrect as tertiary amines cannot form diazonium salts.
4. **Option 4**: Other combinations - These are incorrect as they do not involve primary amines.

### Conclusion
The correct answer is **Option 1**, which involves the reaction of a primary aromatic amine with sodium nitrite and hydrochloric acid to form diazonium salts.

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