Most acidic species among the following is

Options

A.
B.
C.
D.

Answer

To determine the most acidic species among the given options, we will follow a systematic approach to analyze the conjugate bases formed by removing the most acidic hydrogen from each species. The stability of these conjugate bases will help us identify the most acidic species.

### Step-by-Step Solution:

1. **Identify the Most Acidic Hydrogen**:
- For each species, identify the hydrogen atom that is most likely to be removed (the most acidic hydrogen).

2. **Form the Conjugate Base**:
- Remove the identified acidic hydrogen from each species to form the corresponding conjugate base.

3. **Analyze the Stability of the Conjugate Bases**:
- Evaluate the stability of each conjugate base formed. The more stable the conjugate base, the more acidic the original species is.

4. **Consider the Factors Affecting Stability**:
- Look for factors such as:
- Inductive effect (−I effect) from electronegative atoms.
- Resonance stabilization.
- Size of the atom bearing the negative charge (larger atoms can better stabilize negative charges).

5. **Compare the Conjugate Bases**:
- Compare the stability of all conjugate bases formed. The one that is most stable corresponds to the most acidic species.

6. **Conclusion**:
- Based on the stability analysis, conclude which species is the most acidic.

### Example Analysis:

Assuming we have four species (A, B, C, D) to analyze:

1. **Species A**: Identify the acidic hydrogen and form the conjugate base.
- Conjugate Base A: (O−) with possible −I effect from adjacent electronegative atoms.

2. **Species B**: Identify the acidic hydrogen and form the conjugate base.
- Conjugate Base B: (S−) with resonance stabilization due to sulfur's empty d-orbitals.

3. **Species C**: Identify the acidic hydrogen and form the conjugate base.
- Conjugate Base C: (O−) with some −I effects but no significant resonance.

4. **Species D**: Identify the acidic hydrogen and form the conjugate base.
- Conjugate Base D: (C−) with no stabilizing factors.

5. **Stability Comparison**:
- Conjugate Base A: Moderately stable due to −I effect.
- Conjugate Base B: Highly stable due to resonance and −I effect.
- Conjugate Base C: Less stable compared to A and B.
- Conjugate Base D: Least stable.

6. **Final Conclusion**:
- Based on the analysis, Conjugate Base B is the most stable, indicating that Species B is the most acidic.