Of the following reactions, how many reaction, are used for the preparation of amines?
`R - C -= N overset(LiAlH_4) (to)`

Explanation

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

### Step-by-Step Solution:

1. **Identify the Reactants:**
The reaction provided is:
\[ R - C \equiv N \quad \text{(alkyl nitrile)} \]
and the reducing agent is:
\[ \text{LiAlH}_4 \quad \text{(Lithium Aluminium Hydride)} \]

2. **Understand the Reaction Type:**
The reaction involves the reduction of an alkyl nitrile (R-C≡N) to form an amine. Lithium aluminium hydride is a strong reducing agent commonly used in organic chemistry for the reduction of nitriles to primary amines.

3. **Write the Reaction:**
The reduction of the alkyl nitrile can be represented as:
\[ R - C \equiv N + \text{LiAlH}_4 \xrightarrow{\text{ether}} RCH_2NH_2 \]
Here, the product formed is a primary amine (RCH₂NH₂).

4. **Conclusion:**
Since the reaction successfully converts an alkyl nitrile into a primary amine, we conclude that this reaction can indeed be used for the preparation of amines.

### Final Answer:
Thus, there is **1 reaction** that is used for the preparation of amines.

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