Which of the following statement (s) is/are correct ?

Options

A. `3,4,5-`Trinitroaniline (I) than 4-cyano-3,5-dinitroaniline (II)
B. `(II)` is more basic than `(I)`
C. `(I)` is more basic than `(II)` due to steric inhibition of resonance in `(I)`
D. There is no steric inhibition resonance in `(II)`

Answer

To determine which of the statements regarding the basicity of the compounds is correct, we need to analyze the effects of the substituents on the aniline derivatives mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- The first compound is **3,4,5-trinitroaniline**.
- The second compound is **4-cyano-3,5-dinitroaniline**.

2. **Understand Basicity**:
- Basicity in amines is primarily determined by the availability of the lone pair of electrons on the nitrogen atom for donation. The presence of electron-withdrawing groups (EWGs) like nitro (NO2) and cyano (CN) decreases basicity by stabilizing the lone pair through resonance or inductive effects.

3. **Analyze the First Compound (3,4,5-trinitroaniline)**:
- This compound has three nitro groups attached to the benzene ring.
- The nitro groups are strong electron-withdrawing groups and will decrease the basicity of the amine.
- However, due to the arrangement of the nitro groups, the one at the meta position does not participate in resonance with the lone pair of the NH2 group. This leads to **steric inhibition of resonance**, making the lone pair more available for donation.

4. **Analyze the Second Compound (4-cyano-3,5-dinitroaniline)**:
- This compound has two nitro groups and one cyano group.
- The cyano group is planar and can participate in resonance with the benzene ring.
- The presence of the cyano group allows the lone pair on the NH2 group to be delocalized into the ring, thus making it less available for donation and decreasing its basicity.

5. **Compare Basicity**:
- Since the first compound has steric inhibition of resonance, the lone pair on the NH2 group is more available for donation compared to the second compound, where the lone pair is delocalized due to resonance with the cyano group.
- Therefore, **3,4,5-trinitroaniline is more basic than 4-cyano-3,5-dinitroaniline**.

6. **Evaluate the Statements**:
- **Statement 1**: "3,4,5-trinitroaniline is more basic than 4-cyano-3,5-dinitroaniline." - **Correct**
- **Statement 2**: "2 is more basic than 1." - **Incorrect** (as we established that 1 is more basic).
- **Statement 3**: "1 is more basic than 2 due to steric inhibition of resonance in 1." - **Correct**
- **Statement 4**: "There is no steric inhibition of resonance in 2." - **Correct** (the cyano group is planar and participates in resonance).

### Final Conclusion:
- The correct statements are:
- Statement 1: Correct
- Statement 2: Incorrect
- Statement 3: Correct
- Statement 4: Correct