*2. Physical states of reactants and products are mentioned while writing a chemical equation.
Ans. 1. The equation that gives more information about the chemical reaction is known as more informative or information giving equation.
2. The chemical equation can be made more informative in three ways :
(a) By indicating the physical states of reactants and products.
(b) By indicating the heat changes taking place in the equation.
(c) By indicating the conditions under which the reaction takes place. So, physical states of reactants and products are mentioned while writing a chemical equation.