Amongst the following the most basic compound is

Options

A.
B.
C.
D.

Answer

To determine the most basic compound among the given options, we need to analyze the compounds based on the availability of lone pairs of electrons and the stability of their conjugate acids. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
Let's denote the compounds as follows:
1. Compound 1: Aniline (C6H5NH2)
2. Compound 2: 2-Aminoaniline (C6H4(NH2)2)
3. Compound 3: 4-Nitroaniline (C6H4(NO2)(NH2))
4. Compound 4: Benzaldehyde with NH2 (C6H4(CHO)(NH2))

### Step 2: Analyze the Basicity
Basicity in amines is primarily determined by the availability of the lone pair of electrons on the nitrogen atom. The more available the lone pair, the more basic the compound.

### Step 3: Examine Each Compound
- **Compound 1 (Aniline)**: The lone pair on nitrogen can participate in resonance with the benzene ring, reducing its availability.

- **Compound 2 (2-Aminoaniline)**: Similar to aniline, but with an additional NH2 group. The presence of two NH2 groups increases the availability of lone pairs, but resonance still affects it.

- **Compound 3 (4-Nitroaniline)**: The NO2 group is a strong electron-withdrawing group (both -I and -M effects), which decreases the electron density on nitrogen and thus reduces basicity.

- **Compound 4 (Benzaldehyde with NH2)**: The CHO group also has -M and -I effects, which reduce the availability of the lone pair on nitrogen due to resonance.

### Step 4: Compare the Compounds
- **Compound 1** has reduced basicity due to resonance.
- **Compound 2** has the highest availability of lone pairs due to the presence of two NH2 groups, making it more basic.
- **Compound 3** has reduced basicity due to the strong electron-withdrawing effects of the NO2 group.
- **Compound 4** also has reduced basicity due to the resonance effect of the CHO group.

### Conclusion
After analyzing all four compounds, **Compound 2 (2-Aminoaniline)** has the most available lone pairs and is therefore the most basic compound among the options.

### Final Answer
The most basic compound is **Compound 2 (2-Aminoaniline)**.

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