Which of the following statements is correct

Which of the following statements is correct about the reaction given below:

4Fe(s) + 3O2(g) → 2Fe2O3(g)

(i) The total mass of iron and oxygen in reactants = total mass of iron and

oxygen in product therefore it follows the law of conservation of mass.

(ii) The total mass of reactants = total mass of product; therefore, the law of multiple

proportions is followed.

(iii) Amount of Fe2O3 can be increased by taking any one of the reactants

(iron or oxygen) in excess.

(iv) Amount of Fe2O3 produced will decrease if the amount of any one of the

reactants (iron or oxygen) is taken in excess.