Question

(a) What is chemical equation ?

(b) Why it is necessary to balance a chemical equation ?

(c) What are the limitation of a chemical equation ?

Answer 1

(a) Chemical Equation— A chemical equation is the symbolic representation of a chemical reaction
using the symbols and the formulae of the substances involved in the reaction.
(b) A chemical equation needs to be balanced so as to make the number of the atoms of the reactants
equal to the number of the atoms of the products.
(c)
1. It does not inform about the physical states of the reactants and the product i.e. whether they are
solids, liquids and gases.
2. It does not inform about the concentration of reactants and products.
3. It does not inform about the time taken for the completion of the reaction.
4. It does not inform about the rate at which a reaction proceeds.
5. It does not inform about the heat changes during the reaction i. e. whether the heat is given out
or absorbed.
6. It does not inform about the conditions such as temperature, pressure, catalyst etc. which affect
the reaction.
7. It does not inform about the nature of the reaction i.e. whether it is reversible or irreversible.