Selenious Acid is a principle oxoacid of selenium which is prepared by the addition of the selenium dioxide water. It physically appears as a colorless solution which can be used as a reagent for alkaloids and as an oxidizing agent. The chemical has a chemical formula of H2SeO3 with an average molar mass of 128.99 grams per mol. It has a density of 3.00 grams per milliliters at a temperature of 15 degree Celsius with an excellent solubility in water.