A chromate–dichromate equilibrium

In association with

Aqueous solutions of red potassium dichromate and yellow potassium chromate in glass jars

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Try this class practical to investigate an equilibrium between chromate(VI), dichromate(VI) and hydrogen ions. Includes kit list and safety instructions.

In this experiment, students add dilute sulfuric acid to an aqueous solution of potassium chromate(VI). They observe the resulting colour changes, before reversing the reaction using aqueous sodium hydroxide.

The experiment should take no longer than five minutes.

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