Which is the strongest base ?

Options

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B.
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Answer

To determine which is the strongest base among a set of compounds, we need to analyze the ability of each compound to donate a lone pair of electrons. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
First, we need to identify the compounds we are comparing. For this example, let’s assume we are comparing ammonia (NH3), aniline (C6H5NH2), and methylamine (CH3NH2).

### Step 2: Understand the Concept of Basicity
Basicity refers to the ability of a compound to accept protons (H+) or donate a lone pair of electrons. The stronger the base, the more readily it can donate its lone pair of electrons.

### Step 3: Analyze the Lone Pairs
- **Ammonia (NH3)**: It has one lone pair on the nitrogen atom, which is readily available for donation.
- **Aniline (C6H5NH2)**: The lone pair on the nitrogen is partially delocalized into the aromatic ring due to resonance, making it less available for donation.
- **Methylamine (CH3NH2)**: The lone pair on the nitrogen is not involved in resonance and is readily available for donation.

### Step 4: Consider Resonance Effects
- In **aniline**, the resonance with the benzene ring stabilizes the lone pair, reducing its availability to act as a base.
- In **ammonia** and **methylamine**, the lone pairs are localized and can easily participate in protonation.

### Step 5: Compare Basicity
- **Methylamine** is a stronger base than ammonia because the electron-donating effect of the methyl group increases the electron density on nitrogen, making its lone pair more available for donation.
- **Aniline** is the weakest base among the three due to the resonance stabilization of the lone pair.

### Conclusion
Based on the analysis, **methylamine (CH3NH2)** is the strongest base among the compounds compared.