A chemical equation in which the number of atoms of the elements in the reactant is same as the number of atoms of the elements in the products is called as Balanced Equation .
Example::
NaOH+H2SO4 ------> Na2SO4 +H2O -{unbalanced equation }
by multiplying NaOH by 2 we get balanced equation .
2NaOH +H2SO4 ------> Na2SO4 + 2H2O -{balanced equation}