What is meant by oxidation and reduction in terms of oxygen?
Oxidation and reduction are terms used to describe electron movement. They have no specific meaning when referring to oxygen. Oxidation is the loss of electrons from an atom, molecule or ion, whereas reduction is the gain of electrons. Oxidation and reduction can also be described in terms of oxidation numbers. A rise in oxidation number is oxidation and a decrease is reduction. An example of this would be 2Mg + O2 —> 2MgO In this reaction, magnesium of oxidised (it loses two electrons), the oxygen is reduced (as it gains these two electrons). Another example is the decomposition of hydrogen peroxide. 2H2O2 –> 2H2O + O2 The oxidation numbers of H in H2O2 are 1, and O are -1 The states of oxygen change to -2 in H2O and 0 in O2 In this way, the oxygen is both oxidised and reduced. This is called disproportionation.
