Hydrogen does not produce water when it burns. Instead, when hydrogen reacts with oxygen in a process called combustion, it produces water vapor, or H2O. The chemical equation for this reaction is:

2H2 + O2 → 2H2O

In this reaction, two molecules of hydrogen gas (H2) react with one molecule of oxygen gas (O2) to produce two molecules of water vapor (H2O). The water vapor is a colorless, odorless gas that condenses into liquid water at room temperature.