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Reading Selection, Lesson 20

The Electrolysis of Water

In Inquiry 20.1, electricity was used to split water into hydrogen and oxygen. This process is called electrolysis (“electro” refers to electricity and “lysis” means “to break apart”). To break down water through the process of electrolysis, electricity must be able to flow through the water and complete an electrical circuit.

Electricity does not flow easily through pure water because pure water is a poor conductor of electricity, making it difficult to complete an electrical circuit. Adding sodium sulfate to pure water helps the water conduct electricity, which makes it easier to complete an electrical circuit. The energy from the electric current causes a chemical reaction to take place. During the reaction, sodium sulfate does not produce any products that can be detected. All of the gases produced during the electrolysis of water come from the water.

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