The weakest acid among the following is

Options

A. `CH_(3)COOH`
B. `Cl_(2)CHCOOH`
C. `ClCH_(2)COOH`
D. `Cl_(2)C COOH`

Explanation

To determine the weakest acid among the given options, we need to analyze the effects of substituent groups on the acidity of carboxylic acids. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Acid Strength
Acid strength is influenced by the stability of the conjugate base formed after the acid donates a proton (H⁺). The more stable the conjugate base, the stronger the acid. Electron-withdrawing groups (EWGs) stabilize the conjugate base by delocalizing the negative charge, thus increasing acidity.

**Hint:** Remember that electron-withdrawing groups enhance acidity by stabilizing the conjugate base.

### Step 2: Identify the Groups in Each Option
In the given options, we have different substituents attached to the carboxylic acid functional group (-COOH). We need to identify whether these substituents are electron-withdrawing or electron-donating.

**Hint:** Look for groups like halogens (Cl, Br) which are electron-withdrawing, and groups like alkyl (CH₃) which are electron-donating.

### Step 3: Analyze Each Option
- **Option A:** Contains a CH₃ group. Methyl (CH₃) is an electron-donating group, which decreases acidity.
- **Option B:** Contains one Cl atom. Chlorine is an electron-withdrawing group, which increases acidity.
- **Option C:** Contains two Cl atoms. More Cl means stronger electron-withdrawing effect, thus increasing acidity more than one Cl.
- **Option D:** Contains three Cl atoms. The presence of three Cl atoms maximizes the electron-withdrawing effect, making this the strongest acid among the options.

**Hint:** The more electron-withdrawing groups present, the stronger the acid.

### Step 4: Compare Acidity
Now, we compare the acids:
- Option A (CH₃) is the weakest due to the electron-donating effect.
- Options B, C, and D have increasing acidity due to the presence of Cl atoms.

**Hint:** Rank the acids based on the number of electron-withdrawing groups present.

### Step 5: Conclusion
Based on the analysis, the weakest acid among the options is **Option A**, which contains the CH₃ group.

**Final Answer:** The weakest acid among the following is **Option A**.