To solve the question regarding the correct arrangements of compounds based on their acidic or basic properties, we will analyze each option step by step.
### Step 1: Understanding Acidic Strength
1. **Identify the Compounds**: The first option involves carboxylic acids (HCOOH, CH3COOH, and CH3CH2COOH).
2. **Conjugate Base Formation**: For each acid, we will form the conjugate base by removing a proton (H⁺).
- HCOOH → HCOO⁻
- CH3COOH → CH3COO⁻
- CH3CH2COOH → CH3CH2COO⁻
3. **Stability of Conjugate Bases**: The stability of the conjugate base determines the acidity of the original acid. Electron-donating groups (like CH3) destabilize the negative charge, while electron-withdrawing groups stabilize it.
- HCOO⁻ has no electron-donating groups.
- CH3COO⁻ has a methyl group (electron-donating).
- CH3CH2COO⁻ has an ethyl group (more electron-donating than methyl).
4. **Order of Acidity**: The order of acidity based on the stability of the conjugate bases is:
- HCOOH > CH3COOH > CH3CH2COOH
5. **Conclusion for Option A**: This matches the given arrangement, so Option A is correct.
### Step 2: Analyzing Option B
1. **Identify the Compounds**: The second option involves carboxylic acids with halogens (Cl, Br).
- ClCOOH, BrCOOH, and FCOOH.
2. **Conjugate Base Formation**:
- ClCOO⁻, BrCOO⁻, FCOO⁻.
3. **Stability of Conjugate Bases**: Chlorine is more electronegative than bromine, thus it will stabilize the negative charge better than bromine.
4. **Order of Acidity**: The order is:
- FCOOH > ClCOOH > BrCOOH
5. **Conclusion for Option B**: This matches the given arrangement, so Option B is correct.
### Step 3: Analyzing Option C
1. **Identify the Compounds**: The third option involves phenolic compounds and their acidic properties.
- pH-OH, pH-CHO, cyclohexanol.
2. **Conjugate Base Formation**:
- pH-O⁻, pH-CHO⁻, cyclohexanol-O⁻.
3. **Stability of Conjugate Bases**: The phenyl group (pH) can stabilize the negative charge through resonance, while cyclohexanol does not have such stabilization.
4. **Order of Acidity**: The order is:
- pH-OH > pH-CHO > cyclohexanol
5. **Conclusion for Option C**: This matches the given arrangement, so Option C is correct.
### Step 4: Analyzing Option D
1. **Identify the Compounds**: The fourth option involves amines and amides.
- Phenyl amine, cyclohexyl amine, and an amide.
2. **Conjugate Acid Formation**:
- pH-NH3⁺, cyclohexyl-NH3⁺, amide-NH3⁺.
3. **Stability of Conjugate Acids**: The phenyl group is electron-withdrawing, which destabilizes the positive charge on the conjugate acid.
4. **Order of Basicity**: The order is:
- Cyclohexyl amine > Phenyl amine > Amide
5. **Conclusion for Option D**: The arrangement given does not match the order derived, so Option D is incorrect.
### Final Conclusion
The correct options based on the analysis are A, B, and C.
