It is common to observe a reaction where the charges (or more accurately oxidation states) of a reactant change in becoming a product. In doing so, an electron must be gained or lost. The question is where does this electron come from or where does it go? Electrons cannot be created or destroyed, but they can be transferred from one species to another. We need to set up a bookkeeping system to keep track of where these electrons are coming and going and the system that chemists use to do this is assigning oxidation numbers.
4.4 Oxidation Reduction Reactions and Assigning Oxidation Numbers Part 1
4.4 Oxidation Reduction Reactions and Assigning Oxidation Numbers Part 2
Once the rules are established for oxidation-reduction reactions, we can see the relationship between the guidelines given in the previous section and the reactions we observe in the lab. The following video shows you show examples of how to assign oxidation numbers in chemical reactions.
4.4 Assigning Oxidation Numbers Example Problem
Acids can be very corrosive, but they will not dissolve all metals. The “Activity Series” is a guideline allowing a chemist to predict whether an oxidation-reduction reaction will occur. The ability to properly interpret the Activity Series of Metals in Aqueous Solution gives the reader a great deal of information regarding the reactivity of metals in solution.
4.4 Oxidation of Metals by Acids