The effect of concentration changes on chemical equilibria

A8.1b - Chromate(VI) ion and Dichromate(VI) ion equilibria

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Right click and open in new window to view word document with an explanation of the chemistry of the reaction and dynamic equilbrium and a set of questions to ask during a demonstration or video showing.

Right click and open in new window to view a powerpoint presentation showing photographs at the start, after HCl addition and then NaOH addition.

Potassium chromate(VI) solution contains yellow chromate(VI) ions. In acidic solution, orange dichromate(VI) ions are formed. This video demonstrates the addition of acid and alkali to shift the position of equilibrium whch can be observed by the change in colour. This video can be used to aid the understanding of dynamic equilibria and Le Chatelier's principle.

For further information see Salters Advanced Chemistry, 2000, Activities and Assessment Pack, Second Edition, ISBN 0 435 631217