The most acidic among the following is

Options

A. `CH_(3)CH_(2)`OH
B. `C_(6)H_(5)`OH
C. `CH_(3)`COOH
D. `CH_(3)CH_(2)CH_(2)`OH

Explanation

To determine the most acidic compound among the given options, we need to analyze the stability of the conjugate bases formed when each compound donates a proton (H+). The more stable the conjugate base, the stronger the acid.

### Step-by-Step Solution:

1. **Identify the Compounds**:
Let's denote the four options as follows:
- Option A: CH3CH2OH (Ethanol)
- Option B: C6H5OH (Phenol)
- Option C: CH3COOH (Acetic Acid)
- Option D: CH3CH2CH2OH (Butanol)

2. **Determine the Conjugate Bases**:
- For Option A (Ethanol), the conjugate base is CH3CH2O-.
- For Option B (Phenol), the conjugate base is C6H5O-.
- For Option C (Acetic Acid), the conjugate base is CH3COO-.
- For Option D (Butanol), the conjugate base is CH3CH2CH2O-.

3. **Analyze Stability of Conjugate Bases**:
- **Option A (Ethanol)**: The negative charge on the oxygen is not stabilized by any resonance or inductive effects.
- **Option B (Phenol)**: The negative charge can be delocalized over the aromatic ring, providing significant resonance stabilization.
- **Option C (Acetic Acid)**: The negative charge can be delocalized between the two oxygen atoms, providing resonance stabilization.
- **Option D (Butanol)**: Similar to ethanol, the negative charge is not stabilized by resonance.

4. **Compare Stability**:
- **Ethanol and Butanol** have no resonance stabilization for their conjugate bases, making them weaker acids.
- **Phenol** has resonance stabilization due to the aromatic ring, making it more acidic than ethanol and butanol.
- **Acetic Acid** also has resonance stabilization, and the presence of two electronegative oxygen atoms allows for effective delocalization of the negative charge.

5. **Conclusion**:
- Between **Phenol** and **Acetic Acid**, both have resonance stabilization, but the conjugate base of acetic acid (CH3COO-) is more stable due to the ability to delocalize the negative charge over two electronegative atoms (the two oxygens).
- Therefore, **Acetic Acid (Option C)** is the most acidic among the given options.

### Final Answer:
The most acidic compound among the given options is **Option C: CH3COOH (Acetic Acid)**.

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