Balancing the Equation
The chemical equations are based on the law of conservation of mass. According to this law, mass can neither be created nor be destroyed in a chemical reaction. This will be possible only if the total number of each type of atom is the same on the reactant side as well as on the product side of the equation.
Equations in which the number of atoms of different elements in the reactants are the same as the number of atoms on the product side are known as balanced equations.
Al2O3 + H2SO4 Al2(SO4) 3+ H2O ----------(1)
The above equation is an unbalanced one.
There is only 1 atom of sulphur in the reactant side while there is 3 atoms of sulphur in the product side.
Al2O3 + 3H2SO4 Al2(SO4)3 + H2O ------------(2)
Now there are six hydrogen atoms on the reactant side and only two hydrogen atoms in product side. Multiply H2O molecules in the above equation by 3
Now the equation (2) becomes
Al2O3 + 3H2SO4 Al2(SO4)3 + 3H2O -------------(3)
Now in the equation (3) the oxygen atoms are 15 both in reactant and product side. So the final balanced equation isAl2O3 + 3H2SO4 Al2(SO4)3 + 3H2O