Polyhalogen compounds: uses and hazardsपॉलिहैलोजन यौगिक: उपयोग और ख़तरेPolyhalogen compounds: uses and hazards
Class 12 Chemistry · Chapter 6 · interactive diagram
Parts and what they mean
- Dichloromethane (methylene chloride) (डाइक्लोरोमेथेन (मेथिलीन क्लोराइड)) — Solvent, paint remover, aerosol propellant, process solvent for drugs, metal cleaning. Harms the central nervous system; can burn skin and cornea.
- Trichloromethane (chloroform) (ट्राइक्लोरोमेथेन (क्लोरोफ़ॉर्म)) — Solvent for fats and alkaloids; main use today: freon refrigerant R-22. Once an anaesthetic, now replaced by safer ones. ~900 ppm in air causes dizziness, fatigue, headache.
- Triiodomethane (iodoform) (ट्राइआयडोमेथेन (आयडोफ़ॉर्म)) — Was an antiseptic — effect due to liberated free iodine, not iodoform itself; replaced because of its objectionable smell.
- Tetrachloromethane (carbon tetrachloride) (टेट्राक्लोरोमेथेन (कार्बन टेट्राक्लोराइड)) — For refrigerants, aerosol propellants, CFC feedstock, solvent. Possible liver cancer; dizziness, nausea; in air it rises and depletes the ozone layer (more UV → skin cancer, eye disorders).
- Freons (CFCs), e.g. Freon 12 CCl₂F₂ (फ़्रिऑन (CFC), जैसे फ़्रिऑन 12 CCl₂F₂) — Chlorofluorocarbons of methane and ethane: stable, unreactive, non-toxic, easily liquefied. Freon 12 is made from CCl₄ by Swarts reaction. In the stratosphere they start radical chain reactions that upset the ozone balance.
- DDT (p,p′-dichlorodiphenyltrichloroethane) (DDT (p,p′-डाइक्लोरोडाइफ़ेनिलट्राइक्लोरोएथेन)) — First chlorinated organic insecticide (insecticidal effect found by Paul Müller, 1939; Nobel Prize 1948). Insects became resistant; toxic to fish; stable and fat-soluble, so it builds up in fatty tissue. Banned in the USA in 1973.
- Chloroform → phosgene (क्लोरोफ़ॉर्म → फ़ॉस्जीन) — Slow oxidation by air in light gives carbonyl chloride (phosgene), an extremely poisonous gas.
Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake