Le Chatelier's principle: the effect of concentration and temperature on an equilibrium

Description

Changing the chlorine concentration or temperature in this reaction shifts the position of equilibrium, demonstrating Le Chatelier's principle.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
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Apparatus Chemicals

Eye protection (Note 1)

Conical flasks (250 cm3), 2

Two-holed stoppers to fit flasks, 2

U-tube with side-arms

Stoppers to fit U-tube, 2

Large Beakers (1 - 2 dm3), 2

Tap funnel, or separating funnel with stopper

Screw clips (Hoffmann), 2, or Rubber teats (as used for glass dropping pipettes), 2 (Note 2)

Glass tubing, bent as shown in figure

Plastic or rubber tubing for joining glass tubes (as rubber tubing is attacked by chlorine, new tubing should be used for each demonstration)

Access to a fume cupboard

The quantities given are for one demonstration:

Hydrochloric acid, 5 M (IRRITANT at this concentration), about 100 cm3

Sodium chlorate(I) solution (sodium hypochlorite) (10–14% w/v chlorine) (CORROSIVE), about 100cm3(Note 3)

Sodium hydroxide solution, at least 2 M (CORROSIVE), about 100 cm3

Iodine (HARMFUL, DANGEROUS FOR THE ENVIRONMENT), approximately 1 g

Crushed ice, about 250 cm3

Refer to Health & Safety and Technical notes section below for additional information.

 








Page last updated October 2015

Changing the chlorine concentration or temperature in this reaction shifts the position of equilibrium, demonstrating Le Chatelier's principle.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology.