Most acidic hydrogen containing compound among the following is

Options

A.
B.
C.
D.

Answer

To determine which hydrogen-containing compound is the most acidic among the given options, we need to analyze the stability of the conjugate base formed after the release of H⁺ ion. The more stable the conjugate base, the more acidic the original compound.

### Step-by-Step Solution:

1. **Identify the Compounds**:
Let's denote the options as follows:
- Option A: Compound with NO2 groups at meta and para positions.
- Option B: Compound with OH and NO2 at para position.
- Option C: Compound with OH and NO2 at ortho and para positions.
- Option D: Compound with NO2 at meta position.

2. **Understand Acidity**:
Acidity is determined by the ability of a compound to donate H⁺ ions. The stability of the conjugate base (A⁻) formed after losing H⁺ is crucial. The more stable the conjugate base, the stronger the acid.

3. **Analyze the Effects of NO2 Group**:
The NO2 group is an electron-withdrawing group (EWG). It stabilizes the negative charge on the conjugate base through resonance and inductive effects. The more electron-withdrawing groups present, the more stable the conjugate base will be.

4. **Evaluate Each Option**:
- **Option A**: The NO2 groups are at meta and para positions. The conjugate base will have some stabilization due to the para NO2, but the meta NO2 does not contribute to resonance stabilization.
- **Option B**: The para NO2 group will stabilize the conjugate base formed from the hydroxyl group (OH), but only one NO2 group is present.
- **Option C**: The presence of NO2 groups at both ortho and para positions provides significant resonance stabilization to the conjugate base, making it very stable.
- **Option D**: The NO2 group at the meta position does not stabilize the conjugate base effectively.

5. **Conclusion**:
After analyzing the stability of the conjugate bases formed from each option, we find that **Option C** has the most stable conjugate base due to the presence of two NO2 groups (one at ortho and one at para), making it the most acidic compound.

### Final Answer:
**Option C is the most acidic hydrogen-containing compound.**