Formic acid is more acidic than

Options

A. Benzoic acid
B. Acetic acid
C. Phenol
D. Benzene sulphoric acid

Answer

To determine which acids are less acidic than formic acid (HCOOH), we will analyze the acidity of formic acid in comparison to other acids.

### Step-by-Step Solution:

1. **Understanding Formic Acid:**
- Formic acid (HCOOH) is a carboxylic acid. Its structure includes a carbon atom bonded to a hydroxyl group (-OH) and a carbonyl group (C=O).
- When formic acid donates a proton (H⁺), it forms its conjugate base, which is the formate ion (HCOO⁻).

2. **Analyzing the Conjugate Base:**
- The conjugate base of formic acid (HCOO⁻) is stabilized by resonance. The negative charge can be delocalized between the two oxygen atoms, which enhances the stability of the conjugate base.

3. **Comparing with Benzoic Acid:**
- Benzoic acid (C6H5COOH) has a similar structure but includes a benzene ring.
- Its conjugate base (C6H5COO⁻) is also stabilized by resonance, but the resonance involves the benzene ring, which can lead to less effective delocalization of the negative charge compared to formate ion.

4. **Comparing with Acetic Acid:**
- Acetic acid (CH3COOH) has a methyl group attached to the carboxylic acid.
- The conjugate base (CH3COO⁻) is less stable than formate because the methyl group is an electron-donating group (+I effect), which increases the electron density on the conjugate base, making it less stable.

5. **Comparing with Phenol:**
- Phenol (C6H5OH) has a hydroxyl group attached to a benzene ring.
- The conjugate base (C6H5O⁻) is stabilized by resonance with the benzene ring, but it is less acidic than formic acid because the negative charge is localized on one oxygen atom.

6. **Comparing with Benzene Sulfonic Acid:**
- Benzene sulfonic acid (C6H5SO3H) has a sulfonic acid group (-SO3H).
- Its conjugate base (C6H5SO3⁻) is highly stabilized due to the presence of multiple resonance structures involving the sulfonate group, making it more acidic than formic acid.

### Conclusion:
From the analysis, we can conclude that formic acid is more acidic than benzoic acid, acetic acid, and phenol, but less acidic than benzene sulfonic acid. Therefore, the acids that are less acidic than formic acid are:

- Benzoic Acid
- Acetic Acid
- Phenol

### Final Answer:
Formic acid is more acidic than:
1. Benzoic Acid
2. Acetic Acid
3. Phenol