Used in analytical chemistry for calibration and titration procedures, particularly in the determination of oxidizing agents such as chlorine, bromine, and iodine. Commonly employed in water and wastewater treatment testing to measure residual oxidants and ensure proper dechlorination. Also utilized in pharmaceutical and industrial quality control for redox titrations, providing accurate and reproducible results due to its stable and standardized concentration. Suitable for laboratory assays requiring precise sulfur-based reducing agents.