How many of the following substances are more acidic than phenol? O-cresol, m-cresol, water, methyl alcohol, ethyl alcohol, 2,4-dimethylphenol, p-ethylphenol, diimethylcarbinol.

Explanation

To determine how many of the given substances are more acidic than phenol, we need to analyze each substance in relation to phenol's acidity.

### Step-by-Step Solution:

1. **Understanding Phenol's Acidity**:
- Phenol has a pKa value of approximately 10. This means it is a weak acid, but it can donate a proton (H⁺) to form the phenoxide ion.

2. **Analyzing Each Substance**:
- **O-cresol**: This is a methyl-substituted phenol. The methyl group is an electron-donating group (+I effect), which decreases acidity compared to phenol.
- **m-cresol**: Similar to o-cresol, the methyl group also decreases acidity due to its +I effect.
- **Water**: Water has a pKa of about 15.7, making it less acidic than phenol.
- **Methyl alcohol (Methanol)**: Methanol has a pKa of about 15.5, which is also less acidic than phenol.
- **Ethyl alcohol (Ethanol)**: Ethanol has a pKa of about 16, thus it is less acidic than phenol.
- **2,4-Dimethylphenol**: This compound has two methyl groups, which further decrease acidity due to their +I effect, making it less acidic than phenol.
- **p-Ethylphenol**: The ethyl group is also an electron-donating group, making it less acidic than phenol.
- **Diethylcarbinol**: This alcohol is less acidic than phenol, with a pKa greater than 10.

3. **Conclusion**:
- After analyzing all the substances, we find that none of them are more acidic than phenol. Therefore, the answer is **0**.

### Final Answer:
**0 substances are more acidic than phenol.**