Which of the following amine will not respond to carbylamine
reaction ?

Options

A. Ethylamine
B. `(CH_(3))_(2)NH`
C. `CH_(3)NH_(2)`
D. Phenylamine

Answer

To determine which amine will not respond to the carbylamine reaction, we need to understand the requirements for this reaction. The carbylamine reaction, also known as the isocyanide test, is a reaction that occurs specifically with primary amines (1° amines).

### Step-by-Step Solution:

1. **Understanding the Carbylamine Reaction**:
- The carbylamine reaction involves the reaction of a primary amine with chloroform (CHCl3) and a strong base (usually alcoholic KOH) to produce an isocyanide (carbylamine) and other by-products.
- The general reaction can be represented as:
\[ RNH_2 + CHCl_3 + 3KOH \rightarrow R-NC + 3KCl + 3H_2O \]
- The product, R-NC, has a characteristic unpleasant odor.

2. **Identifying the Types of Amines**:
- Amines can be classified as primary (1°), secondary (2°), or tertiary (3°).
- Only primary amines will give a positive carbylamine reaction.

3. **Analyzing the Given Options**:
- **Option 1: Ethylamine (C2H5NH2)** - This is a primary amine and will respond to the carbylamine reaction.
- **Option 2: Phenylamine (Aniline, C6H5NH2)** - This is also a primary aromatic amine and will respond to the carbylamine reaction.
- **Option 3: Dimethylamine (CH3)2NH** - This is a secondary amine and will not respond to the carbylamine reaction.
- **Option 4: Methylamine (CH3NH2)** - This is a primary amine and will respond to the carbylamine reaction.

4. **Conclusion**:
- The amine that will not respond to the carbylamine reaction is **Dimethylamine (Option 3)**, as it is a secondary amine.

### Final Answer:
**Dimethylamine (Option 3) will not respond to the carbylamine reaction.**