Rubidium hydroxide (RbOH) and water (H2O) react to form rubidium oxide (Rb2O) and hydrogen gas (H2). The chemical reaction is as follows:

2RbOH + H2O → Rb2O + 2H2

In this reaction, rubidium hydroxide acts as a base, while water acts as an acid. The hydroxide ions (OH-) from rubidium hydroxide react with the hydronium ions (H3O+) from water to form water molecules and release hydrogen gas. Rubidium oxide is formed as a byproduct of this reaction.