An isonitrile on reduction gives

Options

A. `1^@` amine
B. `2^@` amine
C. `3^@` amine
D. quaternary ammonium salt

Explanation

To solve the question "An isonitrile on reduction gives," we will follow these steps:

### Step 1: Understand the Structure of Isonitrile
Isonitriles, also known as isocyanides, have the functional group -N≡C. The general structure can be represented as R-N≡C, where R is an alkyl or aryl group. For example, methyl isonitrile would be CH3-N≡C.

**Hint:** Recall the structure of isonitriles and their functional group.

### Step 2: Identify the Reduction Process
Reduction typically involves the gain of hydrogen or the loss of oxygen. In the case of isonitriles, reduction will convert the isonitrile group (-N≡C) into an amine. The triple bond between nitrogen and carbon will be reduced to a single bond.

**Hint:** Remember that reduction changes multiple bonds to single bonds by adding hydrogen.

### Step 3: Determine the Product of the Reduction
When an isonitrile undergoes reduction, it will convert to an amine. The nitrogen in the isonitrile will form bonds with hydrogen and carbon. Specifically, the nitrogen will form three bonds: two with carbon atoms (from the original isonitrile and the new hydrogen added) and one with a hydrogen atom.

For example, if we reduce methyl isonitrile (CH3-N≡C), the product will be a secondary amine, specifically dimethylamine (CH3-NH-CH3).

**Hint:** Focus on how many carbon atoms are bonded to the nitrogen after reduction.

### Step 4: Classify the Type of Amine
In the product formed, the nitrogen atom is bonded to two carbon atoms (from the original isonitrile and the new hydrogen added) and one hydrogen atom. This means that the resulting amine is a secondary amine, as it is attached to two carbon groups.

**Hint:** Recall the classification of amines: primary (1 carbon), secondary (2 carbons), tertiary (3 carbons), and quaternary ammonium salts (4 substituents).

### Conclusion
Thus, when an isonitrile is reduced, it gives a secondary amine.

**Final Answer:** The correct answer is **b) secondary amine**.