The materials which allows electric current to pass through them are called good conductor of electricity. Metals are good conductors because of the presence of the free electrons within them. Some of the liquids can also carry current through them. These liquids are called electrolytes. Because of presence of different ions in electrolytic liquids, it is possible for them to conduct electricity. Example of such electrolyte is salt solution.

When electric current passes through any electric current conducting liquid like water, it breaks the liquid into its constituent ions. This is called the process of electrolysis. For the process of electrolysis, current must be passed through the electrolyte via electrodes. The electrode connected to the positive terminal of the battery is known as anode and that connected to the negative terminal of the battery is called cathode.