Match List-I with List-II.
| List-I (Compound) | List-II (Use or property) |
|---|---|
| (A) Dichloromethane | (I) Once used as an antiseptic, but replaced because of its objectionable smell |
| (B) Trichloromethane | (II) Slowly oxidised by air in the presence of light to phosgene |
| (C) Triiodomethane | (III) Used as a paint remover and as a process solvent in the manufacture of drugs |
| (D) Tetrachloromethane | (IV) Used as a spot remover and as a fire extinguisher until the mid 1960s |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A-III, B-II, C-I, D-IV
The four compounds are polyhalogen derivatives of methane, with two, three or four halogen atoms. Each has its own uses and hazards.
(A) Dichloromethane (CH2Cl2, methylene chloride) — This matches (III) Used as a paint remover and as a process solvent in the manufacture of drugs. It is a widely used solvent, also for cleaning and finishing metals.
(B) Trichloromethane (CHCl3, chloroform) — This matches (II) Slowly oxidised by air in the presence of light to phosgene. Phosgene (carbonyl chloride) is extremely poisonous, so chloroform is kept in closed, dark coloured bottles filled completely to keep air out.
(C) Triiodomethane (CHI3, iodoform) — This matches (I) Once used as an antiseptic, but replaced because of its objectionable smell. Its antiseptic action came from the free iodine it liberates, not from iodoform itself.
(D) Tetrachloromethane (CCl4, carbon tetrachloride) — This matches (IV) Used as a spot remover and as a fire extinguisher until the mid 1960s. It was a common cleaning fluid in industry and in the home.
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) – “…Chloroform is slowly oxidised by air in the presence of light to an extremely poisonous gas, carbonyl chloride, also known as phosgene. It is therefore stored in closed dark coloured bottles completely filled so that air is kept out.”
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 Due to its objectionable smell, it has been replaced by other formulations containing iodine.”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) – “…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.”