The balanced chemical equation for the reaction of hydrogen gas and oxygen gas to produce liquid water is:

2 H₂ (g) + O₂ (g) → 2 H₂O (l)

Here's a breakdown:

* 2 H₂ (g): Represents two molecules of hydrogen gas (H₂) in the gaseous state (g).

* O₂ (g): Represents one molecule of oxygen gas (O₂) in the gaseous state (g).

* 2 H₂O (l): Represents two molecules of water (H₂O) in the liquid state (l).

This equation is balanced because:

* There are four hydrogen atoms (2 x 2) on both sides of the equation.

* There are two oxygen atoms on both sides of the equation.