This document summarizes the preparation of chloroform from ethanol and bleaching powder. It describes the reaction steps: 1) bleaching powder produces chlorine when heated with water, 2) the chlorine oxidizes and chlorinates ethanol to form trichloroacetaldehyde, and 3) trichloroacetaldehyde is hydrolyzed by calcium hydroxide to produce chloroform. Some key properties of chloroform are provided, such as its colorless and heavy liquid nature with a sweet smell, boiling point of 334K, toxicity, and former use as an anesthetic.

1. PRESENTED BY
AMAN SINGH CHAUHAN
B.SC (ZBC)
INVERTIS UNIVERSITY BAREILLY

3. Preparation of Chloroform
Chloroform is prepared in the laboratory by heating ethanol with
bleaching powder. The reaction is called Haloform reaction.
When a paste of bleaching powder is heated with ethanol,
chloroform is obtained. The reaction takes place in the following
steps :
 Step 1:
CaOCl² + H²O = Cl² + Ca(OH)²

4. Step 2: Chlorine thus obtained acts as both oxidising and
chlorinating agent. It first oxidises ethanol into acetaldehyde
abd then chlorinates acetaldehyde to give
trichloroacetaldehyde ( chloral) .
CH³CH²OH + CL² = CH³CHO + 2 HCL
Ethanol. Ethanal.
(ethyl alcohol) ( Acetaldehyde)
OXIDATION.

5. CH³CHO + 3Cl² = CCl³ CHO + 3 HCl.
2,2,2– trichloroethanol.
(CHLORINATION)
Step 3: Trichloroacetaldehyde thus formed is hydrolysed by
calcium hydroxide to give chloroform

6. Properties of chloroform
 It is a colourless and heavy liquid with a pecuilar
sickly smell and a sweetish burning taste.
 It is havier than water.
 Generally insoluble in water, but soluble in most
organic solvent.
 Boiling point : 334 K & Freezing point : 210 K
 It’s vapours burns with green edge flame.
 Its vapour when inhaled , causes temporary
unconsciousness. Therefore,formerly. It is used as on
anoesthetic
 It is toxic in nature. It is no longer in use.

7. THANKYOU