combination

Reaction of sodium and chlorine

A small piece of sodium metal is placed in a flask containing chlorine gas. Initially, no reaction is observed, but addition of a drop of water to the sodium initiates a vigorous reaction. Includes close-up replay of reaction.

Reaction of iron with iodine

Powdered iron and powdered iodine are mixed together. Adding drops of water to the mixture initiates a reaction.

Reaction of nickel with iodine

Powdered nickel and powdered iodine are mixed together. Adding drops of water to the mixture fails to initiate a reaction.

Reaction of zinc with iodine

Granular zinc and powdered iodine are mixed together. Adding drops of water to the mixture initiates a reaction.