Product Overview & Quality

Product Name: Sodium thiosulfate pentahydrate
Grade: Analytical Reagent (AR Grade), providing high purity (which features 99.5%) for precise laboratory titrations and environmental analysis.
Physical Properties: Colorless crystals or white crystalline powder; odorless.
Solubility: Readily soluble in water; insoluble in alcohol.
Key Use: Primary standard for iodometric titrations, dechlorination of water, and as a photographic fixing agent.

Safety & Hazards

Classification: Generally recognized as safe (GRAS); non-hazardous under GHS criteria.
Chemical Warning: Reactive with acids. Contact with strong acids releases toxic sulfur dioxide ($SO_2$) gas and precipitates elemental sulfur.
Health Risks: May cause minor mechanical irritation to the eyes, skin, and respiratory tract. It is considered low toxicity.
First Aid Measures: Flush eyes or skin with plenty of water. Move to fresh air if gas or dust is inhaled.

Handling & Storage

Storage: Store in a cool, dry place in a tightly sealed container. The substance is efflorescent (loses water in dry air) and should be kept below 30°C to maintain stability.
Precautions: Wear standard PPE, including gloves and safety goggles. Keep away from strong acids and oxidizing agents.