Why mercury oxide is not used in the preparation of oxygen gas?

Mercury oxide is not used in the preparation of oxygen gas because it is not a suitable reactant for producing oxygen gas through a chemical reaction. Mercury oxide is a compound that contains mercury and oxygen atoms bonded together, and when it is heated, it decomposes to form mercury metal and oxygen gas. However, this reaction is not practical for producing oxygen gas on a large scale because it requires high temperatures and does not yield a high enough amount of oxygen gas compared to other methods such as the decomposition of hydrogen peroxide or the electrolysis of water. Additionally, the use of mercury compounds in chemical reactions is generally avoided due to the toxic nature of mercury.

Mercury oxide is not used in the preparation of oxygen gas because its decomposition reaction is endothermic, meaning it requires energy to occur. In this reaction, mercury oxide decomposes into mercury and oxygen according to the following equation:

2HgO(s) → 2Hg(l) + O2(g)

The enthalpy change for this reaction is positive, indicating that energy is absorbed during the process. This means that external energy must be supplied in order for the reaction to proceed, making it impractical for the production of oxygen gas.