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.
Suggest a substitute for chloroform as a general anaesthetic:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Halothane \((CF_3CHClBr)\)
Chloroform was given up as a general anaesthetic because it depresses the central nervous system and damages the liver and kidneys. It was replaced by less toxic anaesthetics. One of them is the halogen compound halothane, \( \ce{CF3CHClBr} \) (2-bromo-2-chloro-1,1,1-trifluoroethane), which is used as an inhalation anaesthetic during surgery.
Why the other options are incorrect
Option (1) Iodoform \((CHI_3)\) — Incorrect. Iodoform was used as an antiseptic for its iodine; it is not an anaesthetic.
Option (2) Carbon tetrachloride \((CCl_4)\) — Incorrect. A solvent and refrigerant raw material; it is toxic to the liver and nervous system and is not used as an anaesthetic.
Option (3) Pyrene — Incorrect. Pyrene was a trade name of carbon tetrachloride used in fire extinguishers; it has no use as an anaesthetic.
NCERT (2026-27 edition):
Haloalkanes and Haloarenes – “… Our body produces iodine containing hormone, thyroxine, the deficiency of which causes a disease called goiter. Synthetic halogen compounds, viz. chloroquine is used for the treatment of malaria; halothane is used as an anaesthetic during surgery. Certain fully fluorinated compounds are being considered as potential blood substitutes in surgery.”
Trichloromethane (Chloroform) – “… It was once used as a general anaesthetic in surgery but has been replaced by less toxic, safer anaesthetics, such as ether.”