The effect of concentration and temperature on an equilibrium | Le Chatelier’s principle

Solid iodine crystals in a glass beaker, with a purple vapour visible as sublimation occurs

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Try this demonstration to illustrate how changing chlorine concentration or temperature shifts the position of an equilibrium. Includes kit list and safety instructions.

In this experiment, students observe as brown liquid iodine monochloride is formed by passing chlorine gas over solid iodine. Excess chlorine converts this to yellow, solid, iodine trichloride, setting up a heterogeneous equilibrium between these three substances.

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