Question

Chloroform, in the presence of air and sunlight, produces a poisonous gas known as:

• A. Phosgene
• B. Phosphine
• C. Tear gas
• D. Mustard gas

Hint:

To prevent the formation of toxic phosgene gas, chloroform is always stored in dark-coloured, tightly closed bottles filled to the brim.

Answer 1

The Correct Option is A

Step 1: Concept
Haloalkanes like chloroform ($CHCl_3$) are susceptible to oxidation when exposed to atmospheric oxygen and ultraviolet light from the sun.

Step 2: Meaning
This slow photo-oxidation process converts the chloroform into a highly toxic carbonyl compound, making it dangerous for use as an anesthetic if not stored correctly.

Step 3: Analysis
The balanced chemical equation for this reaction is: $2CHCl_3 + O_2 \xrightarrow{\text{light}} 2COCl_2 + 2HCl$. The product $COCl_2$ is carbonyl chloride.

Step 4: Conclusion
Carbonyl chloride is commonly and historically known as phosgene gas, a highly poisonous substance.

Final Answer: (A)