Which of the following compounds is most basics

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds is the most basic, we need to analyze the structure of each compound and how the lone pair of electrons on the nitrogen atom behaves in relation to the rest of the molecule. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Basicity in Amines
Basicity in amines is primarily determined by the availability of the lone pair of electrons on the nitrogen atom. The more available this lone pair is to accept protons (H⁺), the more basic the compound is.

**Hint:** Remember that basicity is related to the lone pair's availability for protonation.

### Step 2: Analyze the Compounds
1. **Option 1**: The nitrogen is directly attached to a benzene ring. The lone pair on nitrogen can be delocalized into the benzene ring through resonance, reducing its availability for protonation.

2. **Option 2**: Similar to option 1, this compound (aniline) has the nitrogen attached to a benzene ring. The lone pair is also delocalized, making it less basic.

3. **Option 3**: This option also features a nitrogen attached to a benzene ring, which means the lone pair is again subject to resonance and delocalization.

4. **Option 4**: In this case, the nitrogen is not directly attached to a benzene ring. This means that the lone pair on nitrogen is not involved in resonance and is more available for protonation.

**Hint:** Look for resonance effects; if the lone pair is delocalized, it is less available for bonding with protons.

### Step 3: Compare Basicity
- Options 1, 2, and 3 have their lone pairs delocalized due to resonance with the benzene ring, which decreases their basicity.
- Option 4 has the lone pair available for protonation since it is not involved in resonance.

**Hint:** The compound with the least resonance stabilization of the lone pair will be the most basic.

### Step 4: Conclusion
Based on the analysis, option 4 is the most basic compound because the lone pair on nitrogen is fully available for protonation without any resonance interference.

**Final Answer:** Option 4 is the most basic compound.