Which of the following is a correctly balanced equation? A. NaClO3 → NaCl + 3O2 B. 2HgO → 2Hg + O2 C. 2ZnS + O2 → 2ZnO + 2SO2 D. 4CO + Fe3O4 → 4CO2 + Fe E. 2Fe + 2Cl2 → 2FeCl3

B. 2HgO → 2Hg + O2

Explanation:

In order to have a correctly balanced equation, you need to have the same amount of elements and molecules of those given elements in both sides of the equation, so in this one there hare 2 molecules of Hg and 2 of Oxygen in the left, and in the rigth, there are 2 Hg, and one molecule of O2 which are 2 molecules of oxygen. So the one that is correctly balanced is B. 2HgO → 2Hg + O2

The correct answer for this is B. Count up the atoms. They should be equal for each side of the equation.