Chemistry Zone Lesson: Electrolytes
An electrolyte is a substance that when dissolved in water forms a solution that can carry an electric current (flow of charge). In the simulation below, each time you click the play button the continuity tester will be placed in a solution. The brighter the light bulb glows, the more current is being conducted by the solution. The stronger the current, the stronger the electrolyte.
The ability of a solution to conduct electricity is the result of ions being present in the solution. Electrolytes include all ionic compounds as well as many polar covalent compounds such as acids that react with water to form ions.
- When you zoom in on the ethyl alcohol notice that the molecules are not attracted to either rod of the continuity tester because the molecules are not charged.
- When you zoom in on acetic acid, some of the molecules have dissociated to form ions. The positively charged Hydrogen ions are attracted to the negatively charged rod and the vice versa for the positively charged rod. This movement of the ions is considered conduction of electric current. Acetic acid is a weak electrolyte because only some of the molecules dissociate to form ions. The remaining molecules are uncharged and do not take part in conducting electric current.
- When you zoom in on the solution of salt (NaCl) you should notice that it is completely dissociated (making it a strong electrolyte) into positive sodium ions and negative chlorine ions. Each ion moves to the oppositely charged rod and again, moving charge is considered an electric current.
The more ions present, the more brightly the light bulb will glow.
