Summary
Highlights
Electrolysis is defined as the flow of electrical current through a liquid, leading to chemical changes. Not all liquids can conduct electricity; they must be a molten ionic compound or an aqueous solution containing free-moving ions.
Using table salt (sodium chloride) as an example, when heated above 801 degrees Celsius, it melts into a liquid containing free-flowing positive sodium ions (cations) and negative chloride ions (anions). These ions are free to move within the liquid.
In metals, electrons move to carry current. In an electrolytic cell, connecting electrodes to a power supply causes one to become positively charged and the other negatively charged. This attracts ions in the molten salt: cations move to the negative electrode and anions to the positive electrode due to electrostatic attraction.
When ions reach the electrodes, electron exchange occurs, triggering chemical reactions. This can result in the formation of solids, gases, or new solutions, depending on the electrolyte and electrode materials.
The positive electrode is called the anode, attracting anions. The negative electrode is called the cathode, attracting cations. A liquid with free-moving ions that can conduct electricity is known as an electrolyte. Electrolysis can occur in both molten compounds and ionic solutions.
The rate of ion flow in an electrolyte can be increased by increasing the concentration of the solution or by increasing the potential difference (voltage) across the cell.
Electrolysis involves electrical current in a conducting liquid (electrolyte) causing chemical changes. Cations are positive ions attracted to the cathode, and anions are negative ions attracted to the anode. In an electrolyte, ions carry the charge, while in electrodes and wires, electrons carry the charge.