Mercury(II) oxide, $\text{HgO}$, breaks down on heating. The equation is shown. $2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2$ Why does this count as a reduction reaction?
- AThe products weigh less than the reactants.
- BThere are fewer reactants than products.
- CThere is a gain of oxygen.
- DThere is a loss of oxygen.