Chloroform easily gets converted to poisonous phosgene in the presence of air and surlight. Which of the following substances is added to prevent the formation of phosgene?

Options

A. Ethanol
B. Sodium carbonate
C. Diethyl carbonate
D. Sodium hydroxide

Answer

To solve the question regarding the prevention of phosgene formation from chloroform, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
Chloroform (CHCl₃) can react with oxygen (O₂) in the presence of sunlight to form phosgene (COCl₂) and hydrochloric acid (HCl). The reaction can be summarized as:
\[ \text{CHCl}_3 + \text{O}_2 \xrightarrow{\text{sunlight}} \text{COCl}_2 + \text{HCl} \]

2. **Identifying the Problem**:
The formation of phosgene is a hazardous reaction, and it is important to find a way to prevent this from happening when chloroform is stored or used.

3. **Exploring the Options**:
We need to determine which of the given substances can be added to chloroform to inhibit the formation of phosgene. The options provided are:
- A) Ethanol (C₂H₅OH)
- B) Sodium carbonate (Na₂CO₃)
- C) Diethyl carbonate (C₅H₁₀O₃)
- D) Sodium hydroxide (NaOH)

4. **Evaluating Ethanol**:
Ethanol is known to react with phosgene to form ethyl carbonate (C₂H₅OCOCl) and hydrochloric acid. The reaction can be represented as:
\[ \text{C}_2\text{H}_5\text{OH} + \text{COCl}_2 \rightarrow \text{C}_2\text{H}_5\text{OCOCl} + \text{HCl} \]
This reaction effectively reduces the concentration of phosgene, preventing its toxic effects.

5. **Conclusion**:
Among the options provided, ethanol is the substance that is commonly added to chloroform to prevent the formation of phosgene. Therefore, the correct answer is:
\[ \text{Option A: Ethanol} \]