Choose the correct statement about chloroform.

(A) It slowly reduces in air in the presence of sunlight to form phosphene gas.
(B) It should be stored in closed dark coloured bottle completely filled to keep air out.
(C) It is when exposed to sunlight in the presence of air forms a gas phosgene.
(D) Chronic chloroform exposure causes damage to liver.

Choose the correct answer from the options given below:

(B), (C) and (D) only

The correct answer is Option (3) → (B), (C) and (D) only.

Let’s break down each statement regarding chloroform and discuss their accuracy in detail.

(A) It slowly reduces in air in the presence of sunlight to form phosphene gas:

This statement is incorrect. Chloroform (\( \text{CHCl}_3 \)) does not reduce to form phosphene gas (\( \text{PH}_3 \)). Instead, chloroform can undergo photodecomposition in the presence of sunlight and oxygen, leading to different byproducts, but phosphene is not one of them. The presence of phosphene is more related to phosphorus compounds rather than chloroform.

(B) It should be stored in a closed dark-colored bottle completely filled to keep air out:

This statement is correct. Chloroform is sensitive to light, which can cause it to decompose into other products over time, including phosgene and hydrochloric acid. Storing chloroform in dark-colored bottles protects it from light. Additionally, filling the bottle completely reduces exposure to air, which can also lead to degradation through oxidation processes.

(C) It is when exposed to sunlight in the presence of air forms a gas phosgene:

This statement is correct. When chloroform is exposed to light and air, it can decompose to produce phosgene (\( \text{COCl}_2 \)), a highly toxic compound. This reaction poses a significant safety risk, making proper storage essential to minimize exposure to light and air.

(D) Chronic chloroform exposure causes damage to the liver:

This statement is correct. Chronic exposure to chloroform has been linked to hepatotoxic effects, meaning it can cause liver damage. Studies have shown that chloroform can lead to liver lesions and other serious liver conditions due to its metabolic products, which can be toxic to liver cells.

Summary of Correct Statements

Statements (B), (C), and (D) are correct, emphasizing the need for safe storage of chloroform, the potential formation of toxic byproducts when exposed to light and air, and the health risks associated with prolonged exposure.

Conclusion

Chloroform is a useful solvent but must be handled with care to avoid toxicity and degradation. Understanding these safety measures is crucial for anyone working with chloroform in a laboratory or industrial setting.