Find the strongest acid among the following compounds is:

Options

A. `HOOC-(CH_(2))_(2)-COOH`
B. `H_(3)N^(o+)-(CH_(2))_(2)-C"OO"H`
C. `F-(CH_(2))_(2)-C"OO"H`
D. `CH_(3)-(CH_(2))_(2)-C"OO"H`

Answer

To determine the strongest acid among the given compounds, we need to analyze the substituents attached to the carboxylic acid group (-COOH) and their effects on acidity. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
First, we need to identify the compounds provided in the question. Let's assume the compounds are:
1. R-COOH (where R = -NH3+, -F, -COOH, -CH3)

### Step 2: Understand the Concept of Acidity
Acidity in organic compounds 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.

### Step 3: Analyze the Substituents
We will analyze the substituents on the carboxylic acid group:
- **-NH3+ (ammonium group)**: This group is a strong electron-withdrawing group due to its positive charge, which stabilizes the negative charge on the conjugate base (R-COO-).
- **-F (fluorine)**: This is a strong electronegative atom that also acts as an electron-withdrawing group, but not as strong as -NH3+.
- **-COOH (carboxylic acid)**: This group can also withdraw electrons but is less effective than -NH3+.
- **-CH3 (methyl group)**: This group is an electron-donating group (+I effect), which destabilizes the conjugate base and decreases acidity.

### Step 4: Determine the Order of Acidity
Based on the effects of the substituents:
1. **-NH3+**: Strongest acid due to strong -I effect.
2. **-F**: Moderate acidity due to -I effect.
3. **-COOH**: Weaker acidity than -F.
4. **-CH3**: Weakest acidity due to +I effect.

### Step 5: Conclusion
The strongest acid among the given compounds is the one with the -NH3+ substituent. Therefore, the answer is:
**R-COOH where R = -NH3+ is the strongest acid.**