The correct order of increasing acidic strength is _____.

Options

A. phenol < ethanol < chloroacetic acid < acetic acid
B. ethanol < phenol < chloroacetic acid < acetic acid
C. ethanol < phenol < acetic acid < chloroacetic acid
D. chloroacetic acid < acetic acid < phenol < ethanol

Answer

To determine the correct order of increasing acidic strength among the given compounds (phenol, ethanol, chloroacetic acid, and acetic acid), we will analyze the acidic nature of each compound step by step.

### Step 1: Identify the Compounds
The compounds given are:
1. Phenol (C6H5OH)
2. Ethanol (C2H5OH)
3. Chloroacetic acid (ClCH2COOH)
4. Acetic acid (CH3COOH)

### Step 2: Understand Acidic Strength
Acidic strength is determined by the ability of a compound to donate a proton (H+). The more stable the conjugate base formed after deprotonation, the stronger the acid.

### Step 3: Compare Alcohols and Acids
- **Phenol and Ethanol**: Both are alcohols. However, phenol is more acidic than ethanol because the phenoxide ion (the conjugate base of phenol) is stabilized by resonance. In contrast, the ethoxide ion (the conjugate base of ethanol) does not have such stabilization.

Thus, we can conclude:
\[ \text{Phenol} > \text{Ethanol} \]

### Step 4: Compare Chloroacetic Acid and Acetic Acid
- **Chloroacetic Acid vs. Acetic Acid**: Chloroacetic acid has a chlorine atom, which is an electron-withdrawing group. This group stabilizes the conjugate base (the chloroacetate ion) through its -I effect, making it easier to lose the proton. Acetic acid, on the other hand, does not have such an electron-withdrawing group and is therefore less acidic.

Thus, we can conclude:
\[ \text{Chloroacetic Acid} > \text{Acetic Acid} \]

### Step 5: Final Comparison
Now we can summarize the acidic strength of the compounds:
1. Ethanol (least acidic)
2. Phenol
3. Acetic Acid
4. Chloroacetic Acid (most acidic)

### Step 6: Order of Increasing Acidity
Putting it all together, the correct order of increasing acidic strength is:
\[ \text{Ethanol} < \text{Phenol} < \text{Acetic Acid} < \text{Chloroacetic Acid} \]

### Final Answer
The correct order of increasing acidic strength is:
**Ethanol < Phenol < Acetic Acid < Chloroacetic Acid**

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