Formic acid acetic acid can be distinguished with

Options

A. sodium
B. `HgCl_2`
C. 2, 4 - dinitropenyl hydrazine
D. `CH_3CH_2overset(-+)(ONa)`

Answer

To distinguish between formic acid (HCOOH) and acetic acid (CH3COOH), we can use a chemical reaction with mercury(II) chloride (HgCl2). Here’s a step-by-step solution:

### Step 1: Understanding the Compounds
- **Formic Acid (HCOOH)**: The simplest carboxylic acid.
- **Acetic Acid (CH3COOH)**: The second simplest carboxylic acid.

### Step 2: Reaction with Mercury(II) Chloride
- When formic acid is treated with mercury(II) chloride, it acts as a reducing agent.
- The reaction can be represented as:
\[ \text{HCOOH} + \text{HgCl}_2 \rightarrow \text{Hg}_2\text{Cl}_2 \text{ (white precipitate)} + 2 \text{HCl} + 2 \text{CO}_2 \text{ (gas)} \]

### Step 3: Observing the Formation of Precipitate
- The formation of a white precipitate (Hg2Cl2) indicates the presence of formic acid.
- In contrast, when acetic acid is treated with mercury(II) chloride, no precipitate is formed:
\[ \text{CH}_3\text{COOH} + \text{HgCl}_2 \rightarrow \text{No precipitate} \]

### Step 4: Conclusion
- If a white precipitate forms, the acid is formic acid.
- If no precipitate forms, the acid is acetic acid.

### Final Answer
Formic acid and acetic acid can be distinguished using mercury(II) chloride (HgCl2).

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