Most acidic among the following is

Options

A.
B.
C.
D.

Answer

To determine which compound is the most acidic among the given options, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compounds**: First, we need to identify the compounds provided in the question. Let's assume we have phenol, p-nitrophenol, and p-cresol (or any other relevant compounds) as our options.

2. **Understand Acidic Strength**: The acidic strength of phenolic compounds is influenced by the substituents attached to the aromatic ring. The presence of electron-withdrawing groups (EWGs) increases acidity, while electron-donating groups (EDGs) decrease acidity.

3. **Analyze Substituents**:
- **NO2 (Nitro Group)**: This is a strong electron-withdrawing group due to its -I (inductive effect) and -R (resonance effect) properties. It stabilizes the negative charge on the phenoxide ion formed after deprotonation of phenol.
- **CH3 (Methyl Group)**: This is an electron-donating group (+I effect). It destabilizes the negative charge on the phenoxide ion, making the compound less acidic.

4. **Evaluate the Effects**:
- For **p-nitrophenol**: The -NO2 group exerts a strong -I and -R effect, making it more acidic.
- For **p-cresol**: The -CH3 group exerts a +I effect, which decreases acidity.

5. **Conclusion**: Based on the analysis of the substituents:
- p-Nitrophenol is more acidic than phenol and p-cresol due to the presence of the electron-withdrawing nitro group.
- Therefore, the most acidic compound among the options is **p-nitrophenol**.

### Final Answer:
The most acidic compound among the given options is **p-nitrophenol**.