Description
Specifications Table
Product Name – Sodium thiosulfate, pentahydrate ARS, ACS
Quantity/Pack Size – 500 g
Form – Crystalline powder
Grade – ARS, ACS
Application – Redox titrations, iodine quantification, dechlorination
Product Overview
Sodium thiosulfate pentahydrate (ARS/ACS grade) is a highly pure, water-soluble crystalline compound essential for analytical chemistry applications. With a minimum assay of 99.0%, it serves as a reliable reducing agent in redox titrations, particularly for iodine quantification where precision is critical. The pentahydrate form ensures stability and consistent performance in aqueous solutions. Its excellent solubility (70 g/100 mL at 20°C) and neutral pH make it compatible with a wide range of laboratory protocols. The ACS-grade certification guarantees compliance with American Chemical Society standards, while the ARS designation confirms its suitability for analytical reagent applications. This product undergoes rigorous quality control to eliminate heavy metal impurities (≤5 ppm for lead, ≤3 ppm for iron), ensuring interference-free results in sensitive analyses. The crystalline structure remains stable under normal storage conditions, though it may effloresce in dry environments. For optimal performance, store in a tightly sealed container away from direct sunlight and moisture.
FAQs
1. What is the difference between ARS and ACS grades in sodium thiosulfate?
ARS (Analytical Reagent Standard) and ACS (American Chemical Society) grades both indicate high purity, but ACS follows stricter heavy metal limits and additional testing parameters specified by the ACS committee.
2. Can this product be used for photographic development processes?
While chemically suitable, this ARS/ACS-grade sodium thiosulfate is optimized for laboratory applications rather than photographic use where lower purity grades are typically sufficient.
3. How should I handle potential caking in the container?
Gently break up any caked material with a clean spatula before use. Avoid crushing the crystals excessively as this may introduce moisture and accelerate caking.
4. What alternatives exist for iodine titration applications?
Sodium arsenite or ascorbic acid can serve as alternatives, though they require different standardization procedures and may have narrower applicable pH ranges compared to thiosulfate.
5. Does this product contain any anti-caking agents?
No anti-caking agents are added to maintain the purity required for ARS/ACS grade specifications. Proper storage conditions are essential to prevent natural caking.
