H₂ + Cl₂ → 2HCl

Here's what the equation represents:

* H₂: Hydrogen gas (diatomic molecule)

* Cl₂: Chlorine gas (diatomic molecule)

* HCl: Hydrogen chloride (also known as hydrochloric acid when dissolved in water)

The equation shows that one molecule of hydrogen gas reacts with one molecule of chlorine gas to produce two molecules of hydrogen chloride.