Benzoic acid is stronger than methanoic acid but weaker than ethanoic acid. True or False

Answer

To determine whether the statement "Benzoic acid is stronger than methanoic acid but weaker than ethanoic acid" is true or false, we need to analyze the acidity of the three acids involved: benzoic acid, methanoic acid, and ethanoic acid.

### Step-by-Step Solution:

1. **Identify the Structures of the Acids**:
- **Methanoic Acid (HCOOH)**: This is the simplest carboxylic acid with no alkyl groups attached to the carboxyl group.
- **Ethanoic Acid (CH3COOH)**: This acid has a methyl group (CH3) attached to the carboxyl group.
- **Benzoic Acid (C6H5COOH)**: This acid has a carboxyl group attached to a benzene ring.

2. **Understanding Acidity**:
- The strength of an acid is often determined by its ability to donate a proton (H+). The stability of the resulting conjugate base also plays a crucial role in acidity.
- The presence of alkyl groups can influence acidity through inductive effects. Alkyl groups generally have a +I (electron-donating) effect, which can destabilize the negative charge on the conjugate base, making the acid weaker.

3. **Comparing Methanoic Acid and Ethanoic Acid**:
- Methanoic acid (HCOOH) does not have any alkyl groups, so it does not experience the destabilizing +I effect.
- Ethanoic acid (CH3COOH) has a methyl group, which exerts a +I effect, increasing electron density on the carboxylate ion (the conjugate base), making it a weaker acid compared to methanoic acid.
- **Conclusion**: Methanoic acid is stronger than ethanoic acid.

4. **Comparing Benzoic Acid and Ethanoic Acid**:
- Benzoic acid has a carboxyl group attached to an sp2 hybridized carbon in the benzene ring. The resonance stabilization provided by the benzene ring can help stabilize the negative charge on the benzoate ion (the conjugate base).
- Ethanoic acid, with its sp3 hybridized carbon, is less stable due to the +I effect of the methyl group.
- **Conclusion**: Benzoic acid is stronger than ethanoic acid.

5. **Final Evaluation of the Statement**:
- The statement claims that benzoic acid is stronger than methanoic acid but weaker than ethanoic acid.
- From our analysis, we found that:
- Methanoic acid > Ethanoic acid
- Benzoic acid > Ethanoic acid
- Therefore, the statement is **False** because benzoic acid is not weaker than methanoic acid.

### Final Answer:
**False**