Oxidation Number Method

Oxidation Number Method: In writing equation for oxidation-reduction reactions, just as for other reactions, the compositions and formulas must be known for the substances that react and for the products that are formed. The oxidation number method is now best illustrated in the following steps below are:

Step 1: write the correct or right formula for each reactant or product.

Step 2: Identify atoms which undergo change in oxidation number to all elements in the reaction.

Step 3: calculate the decrease or increase in the oxidation number per atom and for the molecule /io in which it occurs. If these are not equal than multiply by suitable coefficient so that they become equal. (if you realise that two substances are reduced and nothing is oxidised, something went wrong. Either the formulas of reactants or products are wrong or the oxidisation number have not been assigned properly.)

Step 4: as certain the involvement of ions of the reaction is taking place in water, add  ions to the expression on appropriate side so that  reactants and products are equal. If the reaction is carried out in acidic solution use ions the equation and in basic solution you know.

Step 5: make the numbers of hydrogen atoms in the expression on to sides equal by adding water. Molecules to the reaction is changed by the reaction .