Which of the following compound is expected to be most basic

Options

A. Aniline
B. Methylamine
C. Hydroxylamine
D. Ethylamine

Explanation

To determine which of the given compounds is the most basic, we need to analyze the basicity of each compound based on the structure and the effects of substituents on the nitrogen atom. The compounds in question are:

1. Aniline (C6H5NH2)
2. Methylamine (CH3NH2)
3. Hydroxylamine (NH2OH)
4. Ethylamine (C2H5NH2)

### Step-by-Step Solution:

**Step 1: Analyze Aniline**
- Aniline has a phenyl group attached to the nitrogen atom. The lone pair of electrons on the nitrogen is delocalized into the aromatic ring due to resonance. This delocalization reduces the availability of the lone pair for protonation, making aniline less basic.
- **Conclusion:** Aniline is not the most basic.

**Step 2: Analyze Methylamine**
- Methylamine has a methyl group attached to the nitrogen atom. The methyl group has a +I (positive inductive) effect, which increases the electron density on the nitrogen atom. This makes the lone pair more available for protonation, thus increasing the basicity.
- **Conclusion:** Methylamine is more basic than aniline.

**Step 3: Analyze Hydroxylamine**
- Hydroxylamine has an -OH group attached to the nitrogen. The -OH group has a -I (negative inductive) effect, which pulls electron density away from the nitrogen atom. This decreases the availability of the lone pair for protonation, making hydroxylamine less basic than methylamine.
- **Conclusion:** Hydroxylamine is less basic than methylamine.

**Step 4: Analyze Ethylamine**
- Ethylamine has an ethyl group attached to the nitrogen atom. Similar to methylamine, the ethyl group also exhibits a +I effect, which increases the electron density on the nitrogen atom. The ethyl group is larger than the methyl group, and it exerts a stronger +I effect, making the lone pair on nitrogen even more available for protonation.
- **Conclusion:** Ethylamine is expected to be the most basic among the given compounds.

### Final Conclusion:
Based on the analysis, **ethylamine (C2H5NH2)** is expected to be the most basic compound among the options provided.

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