The most reactive amine towards reactions with dil . HCl is

Options

A. `CH_(3)-NH_(2)`
B.
C. `(CH_(3))_(3)*N`
D.

Explanation

To determine the most reactive amine towards reactions with dilute HCl, we need to analyze the basicity of different types of amines (primary, secondary, and tertiary) and their ability to react with acids.

### Step-by-Step Solution:

1. **Identify the Types of Amines**:
- Amines can be classified into three categories: primary (1°), secondary (2°), and tertiary (3°) amines.
- Example structures:
- Primary amine: CH₃NH₂ (methylamine)
- Secondary amine: (CH₃)₂NH (dimethylamine)
- Tertiary amine: (CH₃)₃N (trimethylamine)

2. **Understand Basicity**:
- Basicity in amines is influenced by the availability of the lone pair of electrons on the nitrogen atom.
- The more available the lone pair, the stronger the base and the more reactive the amine will be towards acids like HCl.

3. **Evaluate the Effect of Alkyl Groups**:
- Alkyl groups are electron-donating and increase the electron density on the nitrogen atom, enhancing basicity.
- As the number of alkyl groups increases, the basicity generally increases due to increased electron donation.

4. **Consider Steric Hindrance**:
- In tertiary amines, the presence of three bulky alkyl groups can create steric hindrance, making it more difficult for the nitrogen to interact with protons (H⁺).
- This steric effect can reduce the reactivity of tertiary amines compared to primary and secondary amines.

5. **Analyze the Reactivity of Each Type**:
- **Primary amines** (like CH₃NH₂) are generally very reactive due to less steric hindrance and good availability of the lone pair.
- **Secondary amines** (like (CH₃)₂NH) are also reactive and have a higher basicity than primary amines due to more alkyl groups.
- **Tertiary amines** (like (CH₃)₃N) have the highest basicity due to three alkyl groups but are less reactive towards acids due to steric hindrance.

6. **Conclusion**:
- Among primary, secondary, and tertiary amines, the **secondary amine** is the most reactive towards dilute HCl because it strikes a balance between basicity and steric hindrance.

### Final Answer:
The most reactive amine towards reactions with dilute HCl is a **secondary amine**.