Here's the balanced chemical equation for the reaction:

4 HCl (aq) + O₂ (g) → 2 Cl₂ (g) + 2 H₂O (l)

Explanation:

* Reactants:

* HCl (aq): Aqueous hydrogen chloride (hydrochloric acid)

* O₂ (g): Oxygen gas

* Products:

* Cl₂ (g): Chlorine gas

* H₂O (l): Liquid water

Balancing the Equation:

* We need 4 moles of HCl to react with 1 mole of O₂ to produce 2 moles of Cl₂ and 2 moles of H₂O.

* The equation is balanced by ensuring that the number of atoms of each element is the same on both sides of the equation.

Note: This reaction is highly exothermic, meaning it releases a significant amount of heat. It's also a redox reaction where hydrogen is oxidized and oxygen is reduced.