Which of the following are not polyhalogen compounds?
1. DDT
2. Freons
3. Chloroform
4. Chloromethane
5. 2-bromobutane
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 4 and 5
Carbon compounds containing more than one halogen atom are called polyhalogen compounds. A compound with only one halogen atom is a monohalogen compound. Counting the halogen atoms:
1. DDT — A polyhalogen compound. p,p′-Dichlorodiphenyltrichloroethane, \( \ce{C14H9Cl5} \), has five chlorine atoms.
2. Freons — A polyhalogen compound. These are chlorofluorocarbons such as \( \ce{CCl2F2} \) (freon-12), with four halogen atoms.
3. Chloroform — A polyhalogen compound. \( \ce{CHCl3} \) (trichloromethane) has three chlorine atoms.
4. Chloromethane — Not a polyhalogen compound. \( \ce{CH3Cl} \) has only one chlorine atom.
5. 2-bromobutane — Not a polyhalogen compound. \( \ce{CH3CHBrCH2CH3} \) has only one bromine atom.
NCERT (2026-27 edition):
Polyhalogen Compounds – …
