Phenol is less acidic than

Options

A. Ethanol
B. Methanol
C. o-Nitrophenol
D. p-Methyl phenol

Answer

To determine which compound is less acidic than phenol, we need to analyze the acidity of phenol and compare it with other compounds based on the influence of electron-donating and electron-withdrawing groups. Here is a step-by-step solution:

### Step 1: Understand the acidity of phenol
Phenol (C6H5OH) is a weak acid that can donate a proton (H+) to form the phenoxide ion (C6H5O-). The acidity of phenol is influenced by the stability of the phenoxide ion formed after deprotonation.

### Step 2: Identify the factors affecting acidity
The acidity of a compound is affected by the presence of electron-withdrawing groups (EWGs) and electron-donating groups (EDGs):
- **Electron-withdrawing groups** stabilize the conjugate base by delocalizing the negative charge, increasing acidity.
- **Electron-donating groups** destabilize the conjugate base by increasing electron density, decreasing acidity.

### Step 3: Compare phenol with ethanol and methanol
1. **Ethanol (C2H5OH)**:
- Ethanol has an ethyl group (C2H5), which is an electron-donating group.
- When ethanol donates a proton, it forms ethoxide ion (C2H5O-), which is less stable due to increased electron density.
- Therefore, ethanol is less acidic than phenol.

2. **Methanol (CH3OH)**:
- Methanol has a methyl group (CH3), which is also an electron-donating group.
- Upon losing a proton, it forms methoxide ion (CH3O-), which is similarly destabilized by the electron-donating effect of the methyl group.
- Thus, methanol is also less acidic than phenol.

### Step 4: Compare phenol with ortho-nitrophenol
- **Ortho-nitrophenol**:
- The nitro group (NO2) is an electron-withdrawing group.
- When ortho-nitrophenol donates a proton, it forms the ortho-nitrophenoxide ion, which is stabilized by the resonance effect of the nitro group.
- Therefore, ortho-nitrophenol is more acidic than phenol.

### Step 5: Compare phenol with para-methylphenol
- **Para-methylphenol**:
- The methyl group (CH3) is an electron-donating group.
- Upon losing a proton, it forms para-methylphenoxide ion, which is destabilized by the electron-donating effect of the methyl group.
- Thus, para-methylphenol is less acidic than phenol.

### Conclusion
From the comparisons made:
- Ethanol and methanol are both less acidic than phenol.
- Ortho-nitrophenol is more acidic than phenol.
- Para-methylphenol is less acidic than phenol.

### Final Answer
Phenol is less acidic than **ethanol** and **methanol**.