Chemical Effects of Electricity

Chemical effects of electricity depend on ions. Recall that ions are electrically charged atoms or groups of atoms. Atoms that gain electrons become negatively charged. Atoms that lose electrons become positively charged.

When two different metal plates are immersed in an electrolyte, one loses electrons and becomes positive. The other gains them and becomes negative. Negative ions in a solution are attracted to the positive plate, and positive ions to the negative plate, and a chemical reaction can occur.

In a lead-acid battery, the electrical and chemical differences between the sets of plates create a potential difference or voltage, which makes the current flow in a circuit. It flows in one direction only, so it is called direct current, or DC. As electrons move through the electrical circuits in the vehicle from one set of plates to the other, the same compounds form on the plates. If this happens for too long, there will be no potential difference between the plates and current stops flowing, leaving a discharged battery. Of course, a battery can be recharged, which reverses the process so that current is pushed backward through the battery, reversing the chemical reaction and restoring the potential difference between its sets of plates.