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 basicity of each compound based on the availability of the lone pair of electrons on the nitrogen atom. Basicity in amines is primarily influenced by the ability of the nitrogen atom to donate its lone pair of electrons.

### Step-by-Step Solution:

1. **Understanding Basicity**:
Basicity refers to the ability of a compound to donate a pair of electrons. In the context of amines, the nitrogen atom has a lone pair that can be donated to a proton (H⁺) or an electrophile.

**Hint**: Remember that the more available the lone pair is for donation, the more basic the compound is.

2. **Analyzing the First Compound**:
The first compound has a nitrogen atom bonded to a benzene ring and a carbonyl group (C=O). The lone pair on nitrogen participates in resonance with the benzene ring and the carbonyl group, making it less available for donation.

**Hint**: Look for resonance structures that involve the lone pair; if it participates in resonance, it is less basic.

3. **Analyzing the Second Compound (Aniline)**:
Aniline (C₆H₅NH₂) has a nitrogen atom with a lone pair that also participates in resonance with the benzene ring. This resonance reduces the availability of the lone pair for donation, thus decreasing its basicity.

**Hint**: Similar to the first compound, check if the lone pair is involved in resonance with an aromatic system.

4. **Analyzing the Third Compound (Nitroaniline)**:
Nitroaniline has a nitro group (NO₂) attached to the benzene ring. The nitro group is an electron-withdrawing group, which pulls electron density away from the nitrogen atom. This further reduces the availability of the lone pair for donation, making it even less basic than aniline.

**Hint**: Electron-withdrawing groups decrease basicity by pulling electron density away from the nitrogen.

5. **Analyzing the Fourth Compound (CH₂NH₂)**:
In this compound, the nitrogen atom is attached to a CH₂ group. The lone pair on nitrogen is not involved in resonance with any electron-withdrawing groups or aromatic systems. Therefore, the lone pair is localized and readily available for donation, making this compound the most basic among the options.

**Hint**: Look for compounds where the lone pair is not involved in resonance or conjugation; these are typically more basic.

6. **Conclusion**:
After analyzing all four compounds, we conclude that the compound with the structure CH₂NH₂ (the fourth option) is the most basic due to the availability of its lone pair for donation.

### Final Answer:
The most basic compound is **D) CH₂NH₂**.