Which of the following is more basic than aniline?

Options

A. Diphenylamine
B. Triphenylamine
C. p-nitroaniline
D. Benzylamine

Explanation

To determine which of the given compounds is more basic than aniline, we need to analyze the basicity of each compound based on the electron-donating ability of their nitrogen lone pairs. Here’s a step-by-step solution:

### Step 1: Understand Aniline's Structure
Aniline (C6H5NH2) consists of a phenyl group (C6H5) attached to an amino group (NH2). The lone pair of electrons on the nitrogen atom can be donated to protons (H+), which is a measure of its basicity.

**Hint:** Basicity in amines is influenced by the availability of the nitrogen lone pair for protonation.

### Step 2: Analyze Diphenylamine
Diphenylamine (C6H5)2NH has two phenyl groups attached to the nitrogen. The presence of these phenyl groups can delocalize the lone pair of electrons on nitrogen through resonance, making it less available for protonation compared to aniline.

**Hint:** Resonance can stabilize the lone pair, reducing basicity.

### Step 3: Analyze Triphenylamine
Triphenylamine (C6H5)3N has three phenyl groups attached to the nitrogen. Similar to diphenylamine, the lone pair on nitrogen is further delocalized, making it even less available for protonation compared to both aniline and diphenylamine.

**Hint:** More phenyl groups lead to greater delocalization and lower basicity.

### Step 4: Analyze Para-Nitroaniline
Para-nitroaniline has a nitro group (-NO2) attached to the para position of the aniline structure. The nitro group is a strong electron-withdrawing group due to its -M (mesomeric) and -I (inductive) effects, which decreases the electron density on the nitrogen, making it less basic than aniline.

**Hint:** Electron-withdrawing groups decrease basicity by reducing electron density on nitrogen.

### Step 5: Analyze Benzylamine
Benzylamine (C6H5CH2NH2) has a benzyl group (C6H5CH2) attached to the amino group. The benzyl group can exert a +I (inductive) effect, which increases the electron density on the nitrogen, making the lone pair more available for protonation compared to aniline.

**Hint:** The +I effect from alkyl groups can enhance basicity.

### Conclusion
Among the compounds analyzed, benzylamine has the highest basicity compared to aniline due to the electron-donating inductive effect of the benzyl group. Therefore, the correct answer is:

**Benzylamine (Option D) is more basic than aniline.**