The key difference between ionization and electrolysis is that ionization is the formation of chemical species having an electrical charge, whereas electrolysis is the process of using an electrical current to carry out a non-spontaneous chemical reaction.
Ionization and electrolysis are very important processes in physical chemistry. There are different ways to carry out an ionization process. Electrolysis can also be used to ionize chemical species.
CONTENTS
1. Overview and Key Difference
2. What is Ionization
3. What is Electrolysis
4. Side by Side Comparison – Ionization vs Electrolysis in Tabular Form
5. Summary
What is Ionization?
Ionization is a chemical process in which atoms or molecules get a positive or negative charge. It occurs due to either removing or obtaining electrons from atoms or molecules, respectively. Here, the resulting ions are named as cations or anions, depending on the charge they have, i.e. cations are positively charged ions and anions are negatively charged ions. Basically, loss of electrons from a neutral atom or a molecule forms a cation and the gain of electrons from a neutral atom gives it a negative charge, forming an anion.
When an electron is removed from a neutral gaseous atom by addition of energy, it forms a monovalent cation. It is because a neutral atom has equal numbers of electrons and protons, resulting in no net charge; when we remove an electron from that atom, there is one excess proton that lacks an electron to neutralize its charge. Therefore, that atom gets a +1 charge (it is the charge of the proton). The amount of energy required for this is the first ionization energy of that atom.
Besides, the ionization that takes place in a liquid solution is the formation of ions in the solution. For example, when HCl molecules dissolve in water, hydronium ions (H3O+) are formed. Here, HCl reacts with water molecules and forms positively charged hydronium ions and negatively charged chloride (Cl–) ions.
Furthermore, ionization may occur through collisions. But, this type of ionization occurs mainly in gases when an electric current passes through the gas. If the electrons in the current have a sufficient amount of energy required to remove electrons from gas molecules, they will force out electrons from gas molecules, producing ion pairs that consist of the individual positive ion and the negative electron. Here, negative ions also form because some electrons tend to attach to gas molecules rather than pulling electrons out.
Figure 01: Ionization Process
Moreover, ionization occurs when radiation energy or sufficiently energetic charged particles pass through solids, liquids or gases; for example, alpha particles, beta particles, and gamma radiation can ionize substances; therefore, we name them as ionizing radiation.
What is Electrolysis?
Electrolysis is the process of using a direct electrical current to drive a non-spontaneous chemical reaction. We can do this using an electrolytic cell. The technique of electrolysis is important to separate a compound into its ions or other components.
In electrolysis, an electric current passes through a solution for the mobility of ions in that solution. An electrolytic cell contains two electrodes immersed in the same solution. And, this solution is the electrolyte. An essential factor in regulating the electrolytic cell is “over potential”. We have to provide a higher voltage in order to carry out a non-spontaneous reaction. Here, an inert electrode can also be used to provide the surface for the reaction that occurs.
Figure 02: Electrolysis of a Salt Solution
There are many applications of electrolysis. One common application is the electrolysis of water. Here, water is the electrolyte. Then the reaction of the breakdown of water molecules into hydrogen and oxygen gases is done using the electric current that is passed through the electrolyte.
What is the Difference Between Ionization and Electrolysis?
Ionization and electrolysis are very important processes in physical chemistry. The key difference between ionization and electrolysis is that ionization is the formation of chemical species having an electrical charge, whereas electrolysis is the process of using an electrical current to carry out a non-spontaneous chemical reaction.
When considering the process, ionization can take place due to several reasons such as the reaction between a neutral species and an ionizing agent, due to collisions, due to ionizing radiation, etc. However, all these methods lead to either the removal or addition of electrons to chemical components, i.e. removal of an electron forms a cation and gaining one electron forms an anion. Electrolysis is also a method that we can use for ionization of compounds. So, this is another difference between ionization and electrolysis.
Summary – Ionization vs Electrolysis
Ionization and electrolysis are very important processes in physical chemistry. The key difference between ionization and electrolysis is that ionization is the formation of chemical species having an electrical charge, whereas electrolysis is the process of using an electrical current to carry out a non-spontaneous chemical reaction.
Reference:
1. Helmenstine, Anne Marie. “Electrolysis Definition in Chemistry.” ThoughtCo, Feb. 7, 2019, Available here.
Image Courtesy:
1. “Electron Ionization” By Evan Mason – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Salt electrolysis” By Sarah.Blumen – Own work (CC BY-SA 4.0) via Commons Wikimedia