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 1: Understanding the Reaction
Chloroform (CHCl₃) can undergo oxidation in the presence of air and sunlight to form phosgene (COCl₂), which is a toxic compound.

### Step 2: Identifying the Additive
To prevent the formation of phosgene, certain substances can be added to chloroform. In this case, ethanol (C₂H₅OH) is commonly used as an additive. Ethanol reacts with chloroform and prevents its oxidation to phosgene.

### Step 3: The Reaction Mechanism
When ethanol is added to chloroform, it can react with the chloroform in the presence of hydrochloric acid (HCl) to form ethyl carbonate, which is a harmless compound. The balanced reaction can be represented as:
\[ 2 \text{C}_2\text{H}_5\text{OH} + \text{HCl} + \text{CHCl}_3 \rightarrow \text{Ethyl Carbonate} + \text{other products} \]

### Step 4: Conclusion
Thus, the substance that is added to prevent the formation of phosgene from chloroform is ethanol (C₂H₅OH).

### Final Answer:
Ethanol (C₂H₅OH) is added to chloroform to prevent the formation of phosgene.

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