Give the Chemical reaction when chloroform reacts with following :

Question

KollegeApply · Accepted Answer

(a) Action of air and light (Oxidation): Chloroform oxidizes in presence of sunlight and air and forms a poisonous gas, phosgene (carbonyl chloride). Ordinary chloroform contains phosgene gas and is used as a solvent. Pure chloroform which is used as an anaesthetic does not contain even traces of phosgene. While preserving chloroform which is to be used as an anaesthetic, the following precautions are taken : (i) The chloroform is filled in blue or brown coloured bottle up to the neck. After putting a stopper, the bottle is kept in dark. As there is no empty space in the bottle, it is also free from air. (ii) One percent ethyl alcohol is added in the bottle. If phosgene gas is formed, alcohol reacts with it to form diethyl carbonate, a non-toxic substance, i.e. (C 2 H 5 ) 2 CO 3 , (b) Carbylamine reaction : On heating chloroform with primary amine (e.g., aniline) and alcoholic KOH solution, phenylisocyanide or carbylamine is formed which has a very bad smell and is poisonous. (c) Reaction with Ag powder or Dehalogenation : On heating chloroform with sil-ver powder, pure acetylene gas is formed. CHCl 3 + 6 Ag + Cl 3 CH $\to$ HC ≡ CH + 6 AgCl (d) Nitration : On treating chloroform with concentrated nitric acid, the hydrogen atom of chloroform is replaced by nitro group and nitro chloroform (or chloropicrin) is formed. It is a liquid (b.p. $112^\circ$C) which is used in war as a poisonous gas. (e) Reimer-Tiemann reaction : On heating chloroform with concentrated alkali and phenol at 60-$70^\circ$C, o-hydroxy benzaldehyde (salicylaldehyde) is formed. Traces of p-hydro- xybenzaldehyde are also formed

AChoose Your Answer