This video explains how to handle material balance problems when more than one reactions are taking place. Particularly two of the concepts, yield and selectivity, have been defined and discussed over here. With the help of a numerical problem, it has been taught how to write the final amount of all the reactants and products in terms of extents of reactions when there are more than one reaction. Yield was given in the problem and it was used to calculate extent of reaction. Selectivity of the desired product over undesired product was also calculated