Consider the following statements about some polyhalogen compounds.
(A) Dichloromethane is used as a paint remover and as a propellant in aerosols.
(B) The major use of chloroform today is in the production of the freon refrigerant R-22.
(C) Carbon tetrachloride was once used as a general anaesthetic in surgery but has been replaced by safer anaesthetics such as ether.
(D) Iodoform was used earlier as an antiseptic, but it has been replaced by other formulations containing iodine because of its high toxicity.
Which of the statements given above are incorrect? Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (C) and (D) only
(A) Dichloromethane is used as a paint remover and as a propellant in aerosols. — Correct statement. Dichloromethane (methylene chloride) is a widely used solvent: as a paint remover, an aerosol propellant, and a process solvent in making drugs.
(B) The major use of chloroform today is in the production of the freon refrigerant R-22. — Correct statement. Chloroform is also a solvent for fats, alkaloids and iodine, but its main use today is making R-22.
(C) Carbon tetrachloride was once used as a general anaesthetic in surgery but has been replaced by safer anaesthetics such as ether. — Incorrect statement. The compound once used as a general anaesthetic is chloroform. Carbon tetrachloride was used as a cleaning fluid, spot remover and fire extinguisher, and in making refrigerants and propellants.
(D) Iodoform was used earlier as an antiseptic, but it has been replaced by other formulations containing iodine because of its high toxicity. — Incorrect statement. Iodoform was replaced because of its objectionable smell. Its antiseptic action came from the free iodine it liberates, which is why other iodine formulations could take its place.
NCERT (2026-27 edition):
6.8.1 Dichloromethane (Methylene chloride) – “Dichloromethane is widely used as a solvent as a paint remover, as a propellant in aerosols, and as a process solvent in the manufacture of drugs.”
6.8.2 Trichloromethane (Chloroform) – “Chemically, chloroform is employed as a solvent for fats, alkaloids, iodine and other substances. The major use of chloroform today is in the production of the freon refrigerant R-22. It was once used as a general anaesthetic in surgery but has been replaced by less toxic, safer anaesthetics, such as ether.”
6.8.3 Triiodomethane (Iodoform) – “It was used earlier as an antiseptic but the antiseptic properties are due to the liberation of free iodine and not due to iodoform itself. Due to its objectionable smell, it has been replaced by other formulations containing iodine.”
6.8.4 Tetrachloromethane (Carbon tetrachloride) – “It is produced in large quantities for use in the manufacture of refrigerants and propellants for aerosol cans. … Until the mid 1960s, it was also widely used as a cleaning fluid, both in industry, as a degreasing agent, and in the home, as a spot remover and as fire extinguisher.”