most basic out of these is :

Options

A. Anilne
B. Benzyl amine
C. M-Nitroaniline
D. P-Nitroaniline

Answer

To determine which amine is the most basic among the given options, we need to analyze the basicity of each compound based on the structure and the effects of substituents on the nitrogen atom. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Compounds
The compounds listed are:
1. Aniline
2. Benzylamine
3. Nitroaniline
4. Meta-nitroaniline
5. Para-nitroaniline

### Step 2: Understand Basicity in Amines
Basicity in amines is influenced by the availability of the lone pair of electrons on the nitrogen atom. The more available the lone pair is, the stronger the base. Factors that affect this availability include:
- Resonance effects
- Inductive effects from substituents

### Step 3: Analyze Aniline
Aniline (C6H5NH2) has a lone pair on the nitrogen that can participate in resonance with the aromatic ring. This delocalization reduces the availability of the lone pair for protonation, making aniline less basic.

### Step 4: Analyze Benzylamine
Benzylamine (C6H5CH2NH2) has a CH2 group between the benzene ring and the amine group. This aliphatic chain prevents resonance from affecting the nitrogen's lone pair, thus maintaining its availability for protonation. Therefore, benzylamine is more basic than aniline.

### Step 5: Analyze Nitroanilines
- **Nitroaniline**: The nitro group (NO2) is an electron-withdrawing group, which decreases the electron density on the nitrogen due to its -I (inductive) and -M (mesomeric) effects. This makes nitroaniline less basic than aniline.
- **Meta-nitroaniline**: The meta position does not allow the -M effect to operate effectively, so it is less affected than para-nitroaniline but still less basic than aniline.
- **Para-nitroaniline**: The nitro group at the para position significantly reduces the basicity of aniline due to both -I and -M effects, making it the least basic among the nitroanilines.

### Step 6: Compare Basicity
Based on the analysis:
- Benzylamine is the most basic due to the absence of resonance effects.
- Aniline is less basic than benzylamine but more basic than nitroanilines.
- Among nitroanilines, meta-nitroaniline is more basic than para-nitroaniline.

### Conclusion
The order of basicity from most basic to least basic is:
1. Benzylamine (most basic)
2. Aniline
3. Meta-nitroaniline
4. Nitroaniline
5. Para-nitroaniline (least basic)

Thus, the most basic amine out of the given options is **Benzylamine**.

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