Acetic acid is obtained when

Options

A. Methyl alcohol is oxidised with potassium permanganate
B. Calcium acetate is distilled in the presence of calcium formate
C. acetaldehyde is oxidised with potassium dichromate and sulphuric acid
D. glycerol is heated with sulphuric acid.

Answer

To solve the question, "Acetic acid is obtained when?", we can follow these steps:

### Step 1: Identify the starting material
The starting material for the production of acetic acid is acetaldehyde (CH3CHO).

### Step 2: Understand the reaction type
Acetic acid can be formed through the oxidation of acetaldehyde. In this process, the aldehyde functional group (-CHO) of acetaldehyde is oxidized to a carboxylic acid functional group (-COOH).

### Step 3: Choose the oxidizing agent
For the oxidation of acetaldehyde to acetic acid, we can use potassium dichromate (K2Cr2O7) as the oxidizing agent. This compound is commonly used in organic chemistry for oxidation reactions.

### Step 4: Include the acidic medium
In addition to the oxidizing agent, sulfuric acid (H2SO4) is often used to provide an acidic medium that facilitates the oxidation process.

### Step 5: Write the balanced chemical equation
The balanced chemical equation for the oxidation of acetaldehyde to acetic acid can be represented as follows:

\[ \text{CH}_3\text{CHO} + \text{[O]} \rightarrow \text{CH}_3\text{COOH} \]

Where [O] represents the oxygen provided by the oxidizing agent (potassium dichromate in acidic medium).

### Step 6: Conclusion
Therefore, acetic acid (CH3COOH) is obtained when acetaldehyde (CH3CHO) is oxidized using potassium dichromate (K2Cr2O7) in the presence of sulfuric acid (H2SO4).

### Final Answer
Acetic acid is obtained when acetaldehyde is oxidized with potassium dichromate and sulfuric acid.

---