H2TeO3, known as tellurous acid, is a chemical compound composed of hydrogen, tellurium, and oxygen. It is a weak acid that can be formed by dissolving tellurium dioxide in water. The compound is often encountered in the study of tellurium chemistry and has applications in various fields, including materials science and analytical chemistry. In its solid form, H2TeO3 appears as a white crystalline substance. It can act as a reducing agent and is used in the synthesis of other tellurium compounds. Its properties and reactions are of interest in both academic research and industrial applications involving tellurium and its derivatives.