Objective:  Students will learn about methods to break bonds by experimenting with electrolysis.

Teacher Notes:

Electrolysis of pure water proceeds slowly because the concentrations of H⁺ and OH^-  ions are too small to carry an appreciable current. The electrical conductivity can be increased by adding H₂SO₄  (an acid) or NaOH (a base), which produce H⁺ and HSO₄^- ions or Na⁺ and OH^- ions. Since the ions carry the electrical current, their presence permits more current to flow through the solution.  Hence more electrons enter and leave the electrolytic cell.

Do not use NaCl (salt) in your liquid to speed up the experiment.  It will create small amounts of chlorine gas.  We suggest using Epsom salt (magnesium sulfate, MgSO₄).  Also note that we recommend 6 volts, although other voltage can work, the higher the voltage the quicker the reaction).

 

You may want to substitute test tubes with graduated cylinders, if you want the students to record the amount of gas collected.