Of the following reactions, how many reaction, are used for the preparation of amines?
`R - overset(overset(O)(||))C- NH_2 overset(Br_(2) + overset(Theta)(O) H) (to)`

Explanation

To determine how many reactions are used for the preparation of amines from the given reaction, we can analyze the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reaction Type**:
The given reaction involves a primary amide (R-C(=O)-NH2) reacting with bromine (Br2) and a hydroxide ion (OH-). This is known as the Hofmann degradation reaction.

**Hint**: Look for the functional groups involved in the reaction to identify the type of reaction.

2. **Understand the Reactants**:
The reactants consist of a primary amide and bromine in the presence of a strong base (KOH). The primary amide is a compound with the functional group -C(=O)-NH2.

**Hint**: Recognize the structure of the primary amide and its significance in the reaction.

3. **Reaction Mechanism**:
In the Hofmann degradation reaction, the primary amide undergoes a reaction with bromine and hydroxide ions, leading to the formation of a primary amine (RNH2). The reaction can be summarized as follows:
\[ R-C(=O)-NH2 + Br2 + 4OH^- \rightarrow RNH2 + K2CO3 + 2KBr + 2H2O \]

**Hint**: Focus on the products formed from the reaction to confirm the formation of amines.

4. **Identify the Product**:
The product of this reaction is a primary amine (RNH2), which confirms that this reaction is indeed used for the preparation of amines.

**Hint**: Check if the product matches the definition of an amine.

5. **Conclusion**:
Since the reaction leads to the formation of a primary amine from a primary amide, we conclude that this reaction is indeed used for the preparation of amines.

**Hint**: Summarize the findings to determine how many reactions are applicable for the preparation of amines.

### Final Answer:
Thus, the given reaction is used for the preparation of amines, and the answer is **1 reaction**.

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