Demonstration of Chloroform

Chemicals needed

Distilled water

Chloral hydrate T    R 25-36/38     S (1/2)-25-45

Sodium hydroxide solution 20%  C    R 35     S (1/2)-26-37/39-45

Dangerous substance information

Trichlormethane Xn    R 22-38-40-48/20/22    S (2)-36/37

Equipment needed

Pear shaped flask (alternative: test tube) with plug

Test procedure

• Safety goggles! Bear in mind toxicity!
• 3 g chloral hydrate is placed in the flask, this is dissolved with a constant swaying motion in 5 ml water.
• Add 2 ml half-concentrated sodium hydroxide solution, plug, under intermittent airing shake a couple of times.
• Left standing the chloroform will settle to the bottom as a colorless, clear, heavy liquid. One can remove some with a pipette and test the smell (very carefully!).

Disposal

• Both phases should be disposed of as halogenated organic waste. The chlorofom can, of course, be kept for other experiments (labelling!)

Elucidation

Due to base catalysis choral hydrate is decomposed into chloroform and formic acid.

CCl3CH(OH)2--> CHCl3 + HCOOH

Photos

Chloroform precipates.

Literature

derived from experiment 1643S, "Chloroform ausChloral", S. 300, [2]