Silicon dioxide (SiO₂) reacts with sodium hydroxide (NaOH) to produce sodium silicate (Na₂SiO₃) and water (H₂O).

The balanced chemical equation for this reaction is:

SiO₂ + 2NaOH → Na₂SiO₃ + H₂O

This reaction is an example of a base-catalyzed hydrolysis, where the sodium hydroxide acts as a catalyst to break down the silicon dioxide. This reaction is commonly used in the manufacturing of glass and other silicate-based materials.