Polyhalogen Compounds

Question

Chloroform stored in a partly filled bottle exposed to light and air slowly becomes poisonous; which oxidation product is responsible for this hazard?

RankGuru · Accepted Answer

Chloroform, trichloromethane, undergoes slow aerial oxidation in the presence of light to form the extremely toxic gas phosgene, also called carbonyl chloride, COCl2. To prevent this, chloroform is stored in dark coloured bottles filled to the brim to exclude air, and about one percent ethanol is added to convert any phosgene formed into harmless ethyl carbonate. Carbon tetrachloride is wrong because it is a separate, fully substituted compound and not the oxidation product of chloroform. Formic acid is incorrect since the oxidation does not stop at a carboxylic acid; the chlorine atoms remain and give an acyl chloride type product. Dichloromethane is wrong because oxidation adds oxygen and removes hydrogen rather than simply removing one chlorine. This matches the NCERT account of why chloroform is stored carefully. Sanity check: replacing the lone C-H of CHCl3 with a C=O and losing one Cl gives COCl2, consistent with phosgene as the oxidation product.

Polyhalogen Compounds

Select the correct option:

🔒 Solution Hidden from View

More organic compounds containing halogens Practice Questions

Chlorobenzene resists nucleophilic substitution under ordinary conditions much more than an alkyl ch...

Two moles of bromoethane are treated with metallic sodium in dry ether under the Wurtz reaction cond...

When 2-bromobutane is heated with alcoholic potassium hydroxide, dehydrohalogenation can give two al...

A chlorofluorocarbon once widely used as an aerosol propellant and refrigerant is implicated in stra...

An enantiomerically pure secondary bromide reacts with cyanide ion by a clean bimolecular substituti...

Converting a primary alcohol into the corresponding chloroalkane using thionyl chloride is often pre...

An alkyl bromide gives an alcohol with aqueous potassium hydroxide but an alkene with alcoholic pota...

Consider 2-chlorobutane prepared as a single batch by free-radical chlorination of butane; how many ...

Arranging methyl, ethyl, isopropyl and tert-butyl bromides by their tendency to undergo unimolecular...

Although chlorine withdraws electrons inductively, nitration of chlorobenzene yields mainly ortho an...

Counting every distinct constitutional structure, how many isomeric monobromides share the molecular...

A student prepares ethylmagnesium bromide in dry ether but accidentally allows moist air into the fl...

About This Question

Solution