Tuesday 16 December 2008

Electrolysis

Electolysis is where we use an electric current to split up an ionic compound that has been dissolved in water.

Our example was sodium chloride solution (salt water)

It contains H+ and OH- ions from the water.
It contains Na+ and Cl- ions from the chlorine.

Two Cl- ions lose 2 electrons at the positive electrode and turn into chlorine gas. It bleached blue litmus paper, turning it white.

The two electrons join up with two H+ ions at the negative electrode to make hydrogen gas.

Na+ and OH- are left behind. This makes sodium hydroxide which is an alkali and turns the universal indicator purple.

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