Used in analytical chemistry for redox titrations, particularly in the determination of oxidizing agents such as potassium permanganate, potassium dichromate, and chlorine. It serves as a reducing agent in quantitative analysis due to its ability to donate electrons in acidic medium. Commonly employed in water and wastewater testing to measure chemical oxygen demand (COD). Also utilized in the calibration of instruments and standardization of other titrants in laboratory settings. Its stable and predictable reactivity makes it suitable for quality control in pharmaceutical and industrial applications where iron content or reducing capacity must be accurately assessed.