The equation for reacting mercury sulfide (HgS) with oxygen (O₂) is:

2 HgS + 3 O₂ → 2 HgO + 2 SO₂

This is a combustion reaction where mercury sulfide reacts with oxygen to produce mercury oxide (HgO) and sulfur dioxide (SO₂).

Here's a breakdown:

* HgS: Mercury sulfide (also known as cinnabar)

* O₂: Oxygen gas

* HgO: Mercury oxide

* SO₂: Sulfur dioxide

Important notes:

* This reaction is highly exothermic, meaning it releases a significant amount of heat.

* Sulfur dioxide is a toxic gas and should be handled with care.

* The reaction is usually carried out at high temperatures to ensure complete combustion.