Potassium hexacyanoruthenate(II) hydrate is primarily used in electrochemical research and applications. It serves as a precursor in the synthesis of ruthenium-based catalysts, which are essential in various catalytic processes, including hydrogenation and oxidation reactions. The compound is also utilized in the development of advanced materials for energy storage, such as supercapacitors and batteries, due to its unique redox properties. Additionally, it finds application in the field of analytical chemistry as a reagent for the detection and quantification of specific ions or molecules. Its stability and solubility in aqueous solutions make it a valuable component in laboratory settings for studying electron transfer processes and designing novel electrochemical sensors.