What is the difference between oxidation and reduction?

Oxidation is the loss of electrons, while reduction is the gain of electrons during a chemical reaction.

In more detail, oxidation and reduction are two key concepts in the field of chemistry, particularly in redox reactions. Oxidation refers to the process where an atom, ion, or molecule loses one or more electrons. This process often involves the substance gaining oxygen or losing hydrogen. For example, when iron reacts with oxygen to form iron(III) oxide, the iron is oxidised because it loses electrons to oxygen.

On the other hand, reduction is the process where an atom, ion, or molecule gains one or more electrons. This often involves the substance losing oxygen or gaining hydrogen. For example, in the reaction between hydrogen and fluorine to form hydrogen fluoride, the fluorine is reduced because it gains an electron from hydrogen.

These two processes always occur together in a redox (reduction-oxidation) reaction. This is because when one substance loses electrons (gets oxidised), another substance must gain those electrons (gets reduced). The substance that gets oxidised is called the reducing agent, because it causes the other substance to be reduced. Similarly, the substance that gets reduced is called the oxidising agent, because it causes the other substance to be oxidised.

Understanding the difference between oxidation and reduction is crucial for understanding many chemical reactions and processes, including combustion, respiration, photosynthesis, and the operation of batteries and fuel cells. It's also important for understanding the concept of oxidation states, which are numbers assigned to atoms that allow chemists to keep track of electron transfer in redox reactions.