Tellurous acid is a chemical compound with the formula H2TeO3. It is an oxoacid of tellurium, which means it contains oxygen, hydrogen, and tellurium. This acid is typically encountered in its salt forms, known as tellurites, which are used in various chemical applications. In its pure form, tellurous acid is a weak acid and can be produced by dissolving tellurium dioxide in water. It is important in the study of inorganic chemistry and has potential applications in materials science and electronics due to its unique properties.