Experiment 9: Redox Reactions

• Oxidation is the loss of electrons in a chemical reaction, and reduction is the gain of electrons. Oxidation–reduction (redox) reactions occur when electrons are transferred from an atom that is oxidized to an atom that is reduced.
• The substance that makes it possible for another substance to be oxidized is

  called either the oxidizing agent OA or the oxidant. The oxidizing agent

  acquires electrons from the other substance and so it is reduced .
• A reducing agent RA or reductant, is a substance that gives up electrons,

  thereby causing another substance to be reduced. The reducing agent is

  therefore oxidized in the process.
• For free elements (uncombined state), each atom has an oxidation number

  of zero.
• In a neutral atom or molecule, the sum of the oxidation numbers must be

  0.
• In a polyatomic ion, the sum of the oxidation numbers of all the atoms in

  the ion must be equal to the charge on the ion.
• Monoatomic ions have oxidation numbers equal to their charge