QS Study

Laboratory Preparation of Chloroform:

CHCl3 is prepared in the laboratory from ethanol or methanone.

Principle: Chloroform is prepared in the laboratory by the action of ethanol with a fine paste of bleaching powder in water. Bleaching powder supplies the chlorine and Ca(OH)2 necessary for reaction; Cl2 acts as an oxidizing agent as well as chlorination agent and Ca(OH)2 is used as an alkali.

Step-1: At first bleaching powder and water (1:2) react to form chlorine and lime water [Ca(OH)2]

Ca(OC1) + H2O = C12 + Ca(OH)2

Step-2: (Oxidation): In this step, ethanol is oxidized by chlorine of bleaching powder to form ethanaldehyde.

CH3 – CH2 – OH + C12 = CH3 – CHO + 2HCl.

Step-3 (Chlorination): The produced ethanaldehyde reacts with chlorine to produce chloral.

CH3 – CHO + 3C12 = C13C – CHO + 3HCl.

Step-4 (Hydrolysis): In this step, the produced chloral undergoes hydrolysis with Ca(OH)2 with the formation of chloroform and calcium formate.

Cl3C – CHO + Ca(OH)2 = 2CHCl3 + (HCOO)2Ca

Uses of Chloroform.

Chloroform is a sweet smelling liquid which is used for the following a purpose.

  • It is used as the solvent for the production of dyes and pesticides.
  • Chloroform is mostly used tools in kidnapping especially in books and movies.
  • Chloroform usually contains heavy metal like deuterium which is used for solvent as Nuclear Magnetic Resonance Spectroscopy.