1.54     describe experiments to investigate electrolysis, using inert electrodes, of aqueous solutions such as sodium chloride, copper(II) sulfate and dilute sulfuric acid and predict  the products

Carry out the experiment as in Section 1.53, but use a beaker of the solution rather than a crucible of molten solid.  Look for bubbles of gas at the electrodes and a coating of a metal on the negative electrode (cathode).  A metal or hydrogen gas will form at the negative electrode (since metal ions and hydrogen ions are positively charged).  Oxygen gas or a halogen (like chlorine, bromine or iodine) will form at the positive electrode (since ions of non-metals are negatively charged).

·        sodium chloride - where there is a reactive metal like sodium, hydrogen from the water is produced in its place. So, this example forms hydrogen at the negative electrode and chlorine at the positive electrode.

·        copper(II) sulfate - where you have an ion like sulphate or hydroxide, oxygen from the water is produced. So, this example forms copper (unreactive metal) at the negative electrode and oxygen at the positive electrode.

·        sulfuric acid - this contains hydrogen ions and sulfate ions. It’s not surprising then that hydrogen forms at the negative electrode and oxygen at the positive electrode.