Answer:2SO2 +4H2 ---> 2S +4H2O
Explanation: elements are made up of atoms and according to Dalton's atomic theory, atoms of elements takes place in a chemical reaction. Balancing a chemical reaction is because of the law of conservative of mass. Balancing a reaction ensure that the amount of the reactants is in perfect relationship with the product. It ensures that the quantity of the reactants will give the products at the end of the reaction.The law of conservative of mass states that in a chemical reaction,mass can not be created or destroyed.
A chemical reaction involves only the separation or rearrangement of atoms. Since matter is not changed during a chemistry reaction,it follows that mass must be conserved too.