Question

Which chemical equation below does not illustrate the Law of Conservation of Mass?

Answer 1

The last chemical equation doesn't follow the law of conservation because there isn't an equal number of zinc

Answer 2

The correct answer is this: 2Zn + 2HCl --> ZnCl2 + H2.

The law of conservation of mass states that matter can neither be created nor destroyed. The implication of this law in chemical equations is that, the number of atoms and molecules that is present in reactants must be equal to those present in the products. That is, for the reactants and the products, the number of atoms and molecules that takes part in the reaction must remain the same, no addition, no subtraction. Looking at the last option given in the question above, one will notice that two zinc atoms are present in the reactants while only one is present in the products, thus, in this case the law of conservation of mass was not obeyed.