When chlorine is passed through acetic acid in presence of halogen carrier (red P), it forms

Options

A. acetyl chloride
B. trichloroacetaldehyde (chloral)
C. trichloroacetic acid
D. methyl chloride.

Answer

To solve the question, "When chlorine is passed through acetic acid in the presence of halogen carrier (red P), it forms," we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are:
- Acetic acid (CH₃COOH)
- Chlorine gas (Cl₂)
- Red phosphorus (P)

### Step 2: Understand the Role of Red Phosphorus
Red phosphorus acts as a halogen carrier, facilitating the substitution of hydrogen atoms in acetic acid with chlorine atoms.

### Step 3: Identify the Alpha Hydrogen
In acetic acid, the alpha hydrogen is the hydrogen atom attached to the carbon adjacent to the carboxyl group (COOH). Acetic acid has three alpha hydrogens (the three hydrogens in the methyl group, CH₃).

### Step 4: Chlorination Process
The chlorination occurs in a stepwise manner:
1. The first alpha hydrogen is replaced by a chlorine atom, forming chloroacetic acid (CH₂ClCOOH).
2. The second alpha hydrogen is replaced by another chlorine atom, resulting in dichloroacetic acid (CHCl₂COOH).
3. Finally, the last alpha hydrogen is replaced, yielding trichloroacetic acid (CCl₃COOH).

### Step 5: Write the Final Product
The final product of the reaction when chlorine is passed through acetic acid in the presence of red phosphorus is trichloroacetic acid (CCl₃COOH).

### Conclusion
Thus, the answer to the question is that the reaction forms **trichloroacetic acid**.

---