Which is the strongest base among the following

Options

A. `C_(6)H_(5)NH_(2)`
B. `p-NO_(2)C_(6)H_(4)NH_(2)`
C. `m-NO_(2)C_(6)H_(4)NH_(2)`
D. `C_(6)H_(5)CH_(2)NH_(2)`

Answer

To determine the strongest base among the given compounds, we can follow these steps:

### Step 1: Identify the Compounds
Let's assume the compounds are:
- A: Aniline (C6H5NH2)
- B: Nitroaniline (C6H4(NH2)(NO2))
- C: Alkylated aniline (C6H5NHR, where R is an alkyl group)
- D: Simple amine (RNH2, where R is an alkyl group)

### Step 2: Understand Basicity
Basicity refers to the ability of a compound to donate a lone pair of electrons. In the context of nitrogen-containing compounds, the basicity is influenced by the hybridization of nitrogen and the presence of electron-withdrawing or electron-donating groups.

### Step 3: Analyze Hybridization
- **Aniline (A)**: The nitrogen in aniline is sp² hybridized, which means it has some resonance with the benzene ring. This resonance delocalizes the lone pair, making it less available for donation.

- **Nitroaniline (B)**: The nitro group (NO2) is an electron-withdrawing group. It decreases the electron density on the nitrogen through resonance and inductive effects, making the lone pair even less available for donation.

- **Alkylated Aniline (C)**: If the alkyl group is an electron-donating group, it can increase the electron density on nitrogen, making it a stronger base than aniline. However, if the alkyl group is not very strong, it may not significantly enhance basicity.

- **Simple Amine (D)**: The nitrogen in simple amines is sp³ hybridized. This means it has a higher availability of the lone pair for donation since there is no resonance effect to delocalize the lone pair.

### Step 4: Compare Basicity
- **Aniline (A)**: Moderate basicity due to sp² hybridization and resonance.
- **Nitroaniline (B)**: Weakest basicity due to the strong electron-withdrawing effect of the nitro group.
- **Alkylated Aniline (C)**: Basicity depends on the strength of the alkyl group.
- **Simple Amine (D)**: Strongest basicity due to sp³ hybridization and no resonance effect.

### Conclusion
Based on the above analysis, the strongest base among the given compounds is **D (Simple Amine)**, as it has the highest availability of the lone pair on nitrogen for donation.