Hydrochloric acid and Electrolysis

Hydrochloric acid and Electrolysis

1. What is electrolysis?

   • Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity. During electrolysis, metals and gases may form at the electrodes.
   • For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or molten (melted). For example, if electricity is passed through copper chloride solution, the copper chloride is broken down to form copper metal and chlorine gas.

2. What happens when hydrochloric acid is electrolysed?

   • Produces chlorine at the positive electrode
   • Produces hydrogen at the negative electrode
   • How to tell if its chlorine or hydrogen produced
     • If the gas produces a squeaky pop from a lighted splint, it is hydrogen
     • If the gas turns blue litmus paper red then white (bleached) it is chlorine.

3. To understand electrolysis, you need to know what an ionic substance is.

   • Ionic substances form when a metal reacts with a non-metal. They contain charged particles called ions. For example, sodium chloride forms when sodium reacts with chlorine. It contains positively charged sodium ions and negatively charged chloride ions. Ionic substances can be broken down by electricity.

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