Which is true about aniline ?

Options

A. The lone pair of N atom is delocalised over the ring
B. It is a stronger base than amine .
C. It is a strong base than cyclohexxyl amine
D. None of above

Answer

To determine which statement about aniline is true, let's analyze the properties and behavior of aniline step by step.

### Step 1: Understand the Structure of Aniline
Aniline is an aromatic amine with the chemical formula C6H5NH2. It consists of a benzene ring (C6H5) attached to an amino group (NH2). The structure can be represented as follows:

```
NH2
|
C6H5 - C6H5
```

### Step 2: Analyze the Basicity of Aniline
The basicity of aniline is influenced by the lone pair of electrons on the nitrogen atom of the amino group. In aniline, this lone pair can participate in resonance with the benzene ring.

- **Resonance Effect**: The lone pair on nitrogen can delocalize into the aromatic ring, reducing its availability to accept protons (H+). This delocalization makes aniline less basic compared to aliphatic amines where the lone pair is not involved in resonance.

### Step 3: Compare Basicity with Other Amines
1. **Aniline vs. Aliphatic Amines**: Aliphatic amines (like methylamine, CH3NH2) do not have resonance stabilization, making them stronger bases than aniline. The inductive effect from the alkyl group increases the electron density on nitrogen, enhancing its ability to donate the lone pair.

2. **Aniline vs. Cyclohexylamine**: Cyclohexylamine is a secondary amine that does not have resonance stabilization like aniline. However, it is generally more basic than aniline because the cyclohexyl group provides a +I (inductive) effect, which increases the electron density on nitrogen.

### Step 4: Evaluate the Given Statements
Now, let's evaluate the statements provided in the question:

1. **The lone pair of nitrogen atom is delocalized in the ring**: This statement is **true**. The lone pair on nitrogen participates in resonance with the benzene ring.

2. **It is a stronger base than amine**: This statement is **false**. Aniline is less basic than aliphatic amines.

3. **It is a stronger base than cyclohexyl amine**: This statement is **false**. Cyclohexylamine is more basic than aniline.

4. **None of the above**: This statement is **false** since the first statement is true.

### Conclusion
The only true statement about aniline is that **the lone pair of nitrogen atom is delocalized in the ring**.