Used in analytical chemistry for redox titrations, particularly in the determination of oxidizing agents such as potassium permanganate, potassium dichromate, and chlorine in water samples. Commonly employed in environmental testing to measure chemical oxygen demand (COD) in wastewater. Also utilized in the pharmaceutical industry for standardization of reagents and quality control of iron content in formulations. Suitable for calibration of instruments and validation of analytical methods requiring a known concentration of ferrous ions.