Answer the question on basis of passage given below:

Chloroform is a very useful solvent for oils, fats and waxes and many organic compounds. It can also be used for preserving biological specimens. Chloroform was used as a general anaesthetic in surgery for a long time but because of its toxic nature, it is no longer used these days.

Why is chloroform stored in dark coloured air tight bottles?

Chloroform reacts with oxygen in presence of sun light.

The correct answer is option 3. Chloroform reacts with oxygen in presence of sun light.

Chloroform \((CHCl_3)\) can undergo reactions with both oxygen and sunlight, leading to chemical changes that can degrade its quality and potentially produce harmful by-products.

1. Reaction with Oxygen: Chloroform can react with oxygen in the air, particularly in the presence of sunlight, through a process called oxidation. This reaction can lead to the formation of compounds such as phosgene \((COCl_2)\) and hydrogen chloride \((HCl)\), which are highly toxic. Phosgene, in particular, was used as a chemical weapon in the past due to its severe toxicity.

2. Reaction with Sunlight: Chloroform is sensitive to light, especially sunlight. When exposed to sunlight, chloroform can undergo photode composition reactions, where it breaks down into other compounds. These reactions can alter the chemical structure of chloroform, leading to the formation of various by-products. Some of these by-products may be harmful or less desirable compared to the original chloroform.

Therefore, storing chloroform in dark-colored bottles helps to minimize its exposure to sunlight, reducing the likelihood of photode composition reactions. Additionally, storing it in airtight containers helps to prevent its exposure to oxygen, further minimizing the risk of oxidation reactions. By minimizing exposure to both oxygen and sunlight, the stability and integrity of chloroform can be preserved during storage.