Which of the following gives carbylamine reaction?

Options

A. `CH_3 CONH_2`
B. `CH_3NH_2`
C. `(CH_3)_2 NH`
D. `C_2 H_5 NO_2`

Explanation

To determine which of the given compounds gives a carbylamine reaction, we need to understand the conditions necessary for this reaction to occur. The carbylamine reaction is a specific reaction involving primary amines.

### Step-by-Step Solution:

1. **Understand the Carbylamine Reaction**:
The carbylamine reaction occurs when a primary amine reacts with chloroform (CHCl3) in the presence of a strong base, typically potassium hydroxide (KOH). The product of this reaction is an isocyanide (carbylamine).

2. **Identify the Requirements**:
- The amine must be a **primary amine**.
- The reaction involves the reagents **CHCl3** and **KOH**.

3. **Examine the Options**:
Let's analyze each option to identify if it contains a primary amine:
- **Option A**: Check if it is a primary amine.
- **Option B**: CH3NH2 (methylamine) is a primary amine.
- **Option C**: Check if it is a primary amine.
- **Option D**: Check if it is a primary amine.

4. **Determine Which Option is a Primary Amine**:
- **Option A**: Not a primary amine (e.g., could be an amide).
- **Option B**: CH3NH2 is a primary amine, thus it can undergo the carbylamine reaction.
- **Option C**: Not a primary amine (e.g., could be a secondary amine).
- **Option D**: Not a primary amine (contains a nitro group).

5. **Conclusion**:
Based on the analysis, **Option B (CH3NH2)** is the only primary amine that will undergo the carbylamine reaction with CHCl3 and KOH to produce methyl isocyanide (CH3NC).

Therefore, the answer is **Option B**.