Which of the following statements is correct ?

Options

A. Phenol is less acidic than ethyl alcohol
B. Phenol is more acidic than ethyl alcohol
C. Phenol is more acidic than carboxylic acid
D. Phenol is more acidic than carbonic acid

Answer

To determine which of the statements regarding the acidity of phenol, ethyl alcohol, carboxylic acid, and carbonic acid is correct, we will analyze the acidity of each compound step by step.

### Step 1: Identify the Compounds
The compounds we are comparing are:
1. Phenol (C6H5OH or pH OH)
2. Ethyl Alcohol (C2H5OH)
3. Carboxylic Acid (RCOOH)
4. Carbonic Acid (H2CO3)

### Step 2: Understand Acidity
Acidity is determined by the ability of a compound to donate a proton (H+). The more readily a compound donates a proton, the stronger the acid.

### Step 3: Analyze the Acidity of Each Compound
1. **Carboxylic Acid (RCOOH)**:
- Carboxylic acids are known to be strong acids due to the resonance stabilization of the carboxylate ion (RCOO-) formed after deprotonation.
- They have a high -I (inductive effect) which stabilizes the negative charge on the conjugate base.

2. **Carbonic Acid (H2CO3)**:
- Carbonic acid is a weak acid, but it can dissociate to form bicarbonate (HCO3-) and carbonate (CO3^2-).
- Its acidity is lower than that of carboxylic acids but higher than that of alcohols.

3. **Phenol (C6H5OH)**:
- Phenol can donate a proton to form phenoxide ion (C6H5O-), which is stabilized by resonance.
- The resonance structures allow the negative charge to be delocalized, making phenol more acidic than alcohols.

4. **Ethyl Alcohol (C2H5OH)**:
- Ethyl alcohol is a weak acid and does not stabilize the conjugate base as effectively as phenol.
- It has no significant resonance stabilization after losing a proton.

### Step 4: Order of Acidity
Based on the analysis:
- **Carboxylic Acid (RCOOH)** > **Carbonic Acid (H2CO3)** > **Phenol (C6H5OH)** > **Ethyl Alcohol (C2H5OH)**

### Step 5: Evaluate the Statements
Now we can evaluate the provided statements:
- **A**: Phenol is less acidic than ethyl alcohol. **(Incorrect)**
- **B**: Phenol is more acidic than ethyl alcohol. **(Correct)**
- **C**: Phenol is more acidic than carboxylic acid. **(Incorrect)**
- **D**: Phenol is more acidic than carbonic acid. **(Incorrect)**

### Conclusion
The correct statement is **B**: Phenol is more acidic than ethyl alcohol.

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