Which of the following statements is correct regarding formic acid ?

Options

A. It is a reducing agent.
B. It is a weaker acid than acetic acid.
C. It is an oxidising agent.
D. When its calcium salt is heated it forms acetone.

Answer

To determine which statement is correct regarding formic acid, let's analyze the properties and characteristics of formic acid step by step.

### Step 1: Identify the Chemical Structure of Formic Acid
Formic acid is the simplest carboxylic acid and its chemical formula is \( \text{HCOOH} \) or \( \text{HC}(=O)\text{OH} \).

### Step 2: Determine the Acidic Strength of Formic Acid
To compare the acidity of formic acid with acetic acid (which has the formula \( \text{CH}_3\text{COOH} \)), we need to understand how easily each can donate a proton (\( \text{H}^+ \)).

- Formic acid can dissociate to form the formate ion (\( \text{HCOO}^- \)).
- Acetic acid dissociates to form the acetate ion (\( \text{CH}_3\text{COO}^- \)).

### Step 3: Analyze the Stability of the Conjugate Bases
- The formate ion (\( \text{HCOO}^- \)) does not have any electron-donating groups, making it more stable.
- The acetate ion (\( \text{CH}_3\text{COO}^- \)) has a methyl group (\( \text{CH}_3 \)), which is an electron-donating group. This makes the acetate ion less stable compared to the formate ion.

### Step 4: Conclusion on Acidity
Since the formate ion is more stable than the acetate ion, formic acid is a stronger acid than acetic acid. Therefore, the statement that formic acid is a weaker acid than acetic acid is incorrect.

### Step 5: Reducing Agent Property
Formic acid acts as a reducing agent. It can reduce certain compounds, including Tollen's reagent and Fehling's solution. This property confirms that formic acid is indeed a reducing agent.

### Step 6: Heating Calcium Salt of Formic Acid
When the calcium salt of formic acid is heated, it decomposes to form formaldehyde and calcium carbonate. This indicates that the statement regarding the formation of acetic acid is incorrect.

### Final Answer
The correct statement regarding formic acid is that it acts as a reducing agent.

### Summary of Options:
- Option A: Correct (Formic acid is a reducing agent)
- Option B: Incorrect (Formic acid is stronger than acetic acid)
- Option C: Incorrect (Formic acid does not form acetic acid when heated)
- Option D: Incorrect (Formic acid forms formaldehyde when heated)