Which of the following is the most acidic alcohol ?

Options

A. `(CH_(3)) _(3) C-OH`
B. `CH_(3) CH_(2) OH`
C. `CH_(3) OH`
D. Propanol -2

Answer

To determine which of the given alcohols is the most acidic, we need to analyze the effect of substituents on the acidity of alcohols.

### Step-by-Step Solution:

1. **Understanding Acidity in Alcohols**:
- The acidity of alcohols is influenced by the presence of electron-donating or electron-withdrawing groups.
- Electron-donating groups (like alkyl groups) decrease acidity because they increase electron density around the hydroxyl (–OH) group, making it harder to release H⁺ ions.
- Conversely, electron-withdrawing groups increase acidity by stabilizing the negative charge on the alkoxide ion formed when H⁺ is released.

2. **Analyzing the Given Options**:
- Let's consider the options provided:
- A) \( \text{(CH}_3)_3\text{COH} \) (tert-Butyl alcohol)
- B) \( \text{CH}_3\text{CH}_2\text{OH} \) (Ethanol)
- C) \( \text{CH}_3\text{OH} \) (Methanol)
- D) \( \text{CH}_3\text{CHOHCH}_3 \) (Propan-2-ol)

3. **Evaluating Each Alcohol**:
- **A) tert-Butyl alcohol (\( \text{(CH}_3)_3\text{COH} \))**:
- It has three methyl groups which are strong electron donors via the +I effect. This increases the electron density around the –OH bond, making it less acidic.

- **B) Ethanol (\( \text{CH}_3\text{CH}_2\text{OH} \))**:
- Ethanol has one methyl group donating electrons, which also decreases acidity but is less than tert-butyl alcohol.

- **C) Methanol (\( \text{CH}_3\text{OH} \))**:
- Methanol has only one methyl group donating electrons. The electron density around the –OH bond is lower compared to the previous two, making it more acidic than both tert-butyl and ethanol.

- **D) Propan-2-ol (\( \text{CH}_3\text{CHOHCH}_3 \))**:
- Propan-2-ol has two methyl groups donating electrons, which decreases acidity more than methanol but less than tert-butyl alcohol.

4. **Conclusion**:
- Among all the options, methanol (\( \text{CH}_3\text{OH} \)) has the least electron-donating effect due to having only one methyl group. Therefore, it is the most acidic alcohol among the given options.

### Final Answer:
The most acidic alcohol is **C) Methanol (\( \text{CH}_3\text{OH} \))**.

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