Formic acid can be distinguish from acetic acid because formic acid

Options

A. release `H_(2)` with sodium
B. gives ester with alcohol
C. reduces ammonical `AgNO_(3)`
D. turns red litmus to blue

Answer

To distinguish formic acid from acetic acid, we need to analyze their chemical properties and reactions. Here’s a step-by-step solution:

### Step 1: Understand the Structures
- **Formic Acid (HCOOH)**: It has the structure H-C(=O)-OH.
- **Acetic Acid (CH3COOH)**: It has the structure CH3-C(=O)-OH.

### Step 2: Identify Key Differences
- Both acids contain a carboxylic group (-COOH) and can undergo similar reactions, but we need to find a reaction that distinguishes them.

### Step 3: Active Hydrogen Test
- Both formic acid and acetic acid can react with active metals (like sodium) to release hydrogen gas. Therefore, this test cannot distinguish between the two.

### Step 4: Esterification Reaction
- Both acids can react with alcohols to form esters. Thus, this reaction also does not serve as a distinguishing factor.

### Step 5: Reaction with Ammonical AgNO3
- Formic acid can reduce ammonical silver nitrate (AgNO3) due to the presence of a hydrogen atom attached to the carbon that is also bonded to the carbonyl oxygen (C=O). This hydrogen is known as reducing hydrogen.
- Acetic acid does not have this reducing hydrogen because the carbon attached to the carbonyl group has three hydrogens (in CH3), which do not participate in reduction.

### Step 6: Litmus Test
- Both acids will turn blue litmus paper red, as they are both acids. Therefore, this test cannot distinguish between them.

### Conclusion
- The key distinguishing reaction is that **formic acid reduces ammonical AgNO3**, while **acetic acid does not**. This is due to the presence of reducing hydrogen in formic acid.

### Final Answer
Formic acid can be distinguished from acetic acid because formic acid reduces ammonical AgNO3, while acetic acid does not.

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