Which of the following is added to chloroform to slow down its aerial oxidationin presence of light ?

Options

A. Carbonyl chloride
B. Ethyl alcohol
C. Sodium hydroxide
D. Nitric acid

Explanation

To solve the question regarding which substance is added to chloroform to slow down its aerial oxidation in the presence of light, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Problem**:
Chloroform (CHCl3) can undergo oxidation when exposed to light and air, leading to the formation of phosgene (COCl2), a highly toxic gas. The goal is to find a substance that can inhibit this reaction.

**Hint**: Identify the chemical behavior of chloroform when exposed to light and air.

2. **Identify the Reaction**:
When chloroform is exposed to light, it can react with oxygen in the air, resulting in the formation of phosgene and hydrochloric acid (HCl). This reaction is undesirable due to the toxicity of phosgene.

**Hint**: Recall the products formed during the oxidation of chloroform.

3. **Research Inhibitors**:
To prevent or slow down the oxidation of chloroform, certain substances known as negative catalysts or inhibitors can be used. These substances do not participate in the reaction but help to decrease the rate of oxidation.

**Hint**: Look for common inhibitors used in organic chemistry to slow down oxidation reactions.

4. **Identify the Correct Substance**:
Ethyl alcohol (ethanol, C2H5OH) is known to act as a negative catalyst in this context. It can be added to chloroform to slow down the oxidation process by stabilizing the chloroform and preventing the formation of phosgene.

**Hint**: Consider the properties of ethyl alcohol and its role in chemical reactions.

5. **Conclusion**:
Based on the information gathered, the correct answer to the question is that ethyl alcohol is added to chloroform to slow down its aerial oxidation in the presence of light.

**Final Answer**: Ethyl alcohol (Option B).