Sodium sulfite 98% or Disodium sulfite or Sulfurous acid disodium salt anhydrous

Product Overview & Quality

• Product Name: Sodium sulfite 98% or Disodium sulfite or Sulfurous acid disodium salt anhydrous
• Brand: QReC (Product Code: QR-S5303-1-0500)
• Grade: Analytical Reagent High Purity Grade (AR Grade) featuring a certified chemical assay of not less than 98.0 percent in a convenient 500 g laboratory container. Manufactured, crystallized, and dried under strict QReC global laboratory specifications without anti-caking conditioning agents. Strictly tested to enforce minimal water-insoluble matter (strictly below 0.005 percent), alongside minimal ppm thresholds of chloride, thiosulfate, and trace heavy metals (such as iron, lead, copper, arsenic, zinc, and selenium). Dry, uniform white crystalline powder dissolving completely in water to yield clear, neutral-to-alkaline, particulate-free solutions. Packaged in a heavy-duty, moisture-barrier polymer container equipped with an airtight hermetic seal to prevent aerial oxidation and moisture degradation.
• Physical Properties: White fine crystalline powder or small granular crystals. Odorless to faint sulfurous odor (resembling sulfur dioxide). Saline, slightly sulfurous taste. Stable in dry air under ambient conditions, but undergoes slow aerial oxidation to sodium sulfate in the presence of atmospheric moisture. Non-combustible inorganic salt. Aqueous solutions are mildly alkaline (pH approximately 8.5 to 10.0 for a 5 percent aqueous solution at room temperature).
• Solubility: Readily and highly soluble in water (approximately 22 to 25 grams per 100 milliliters at 20 degrees Celsius, reaching approximately 28 grams per 100 milliliters at 33.4 degrees Celsius; above this transition temperature, solubility slightly decreases with rising temperature due to retrograde solubility behavior); soluble in glycerol; practically insoluble in ethanol.
• Key Use: Universally utilized as a classical inorganic reducing agent and quenching reagent in synthetic organic chemistry to reduce and neutralize residual halogens (such as bromine and iodine), hypochlorites, and peroxides during post-reaction workups. Extensively applied as a dissolved oxygen scavenger and antioxidant preservative to protect oxygen-sensitive chemical reagents, photographic developer solutions, and biological test matrices from spontaneous aerial degradation. Serves as a vital chemical intermediate for synthesizing sulfur-containing compounds, including sodium thiosulfate and sulfonated organic derivatives. Heavily employed in environmental analytical testing and wastewater monitoring to dechlorinate water samples prior to bacteriological or chemical testing. Functions as an analytical reference standard and buffer component in routine wet chemical analysis.

Safety & Hazards (Toxic Gas Liberation with Acids, Mild Irritant & Sulfite Sensitivity)

• Classification: Contact with acids liberates toxic gas (EUH031). May cause mild ocular, dermal, and respiratory tract irritation.
• Health Risks: Direct ocular contact may cause transient stinging pain, mild conjunctival redness, or lacrimation. Prolonged dermal exposure may cause mild dryness or superficial irritation. Inhalation of particulate dust irritates the mucous membranes of the respiratory tract, provoking sneezing, coughing, and throat dryness. Critical Precaution: Individuals with pre-existing asthma or sulfite hypersensitivity may suffer severe bronchospasms, dyspnea, or anaphylactoid allergic reactions upon exposure. Acidification liberates toxic, pungent, and suffocating sulfur dioxide gas, which aggressively attacks mucosal linings. Ingestion of excessive quantities provokes gastrointestinal irritation, abdominal pain, nausea, vomiting, and diarrhea.
• First Aid Measures: Flush affected eyes thoroughly with clean running water for at least 15 minutes while stripping contaminated clothing; remove contact lenses promptly. Wash exposed skin with soap and water. In case of dust or sulfur dioxide gas inhalation, relocate the individual to fresh air immediately; seek prompt medical evaluation if breathing difficulties occur. If accidentally swallowed in substantial amounts, rinse mouth thoroughly, administer water in moderate amounts, and seek medical advice promptly.

Handling & Storage

• Storage: Air-Sensitive Reducing Salt with Severe Acid Incompatibility. Ambient humidity accelerates slow oxidation to sulfate. Must be preserved in its original, tightly closed QReC container. Store in a clean, strictly dry, cool, and well-ventilated dedicated chemical store at controlled temperatures (below 25 to 30 degrees Celsius), sheltered from atmospheric humidity and direct sunlight. “Critical Incompatibility Mandate: Keep strictly segregated from strong mineral acids (contact instantaneously liberates toxic, choking sulfur dioxide gas) and strong oxidizing agents (such as chlorates, permanganates, nitrates, and peroxides).”
• Precautions: Standard laboratory PPE is mandatory, including protective nitrile gloves, safety glasses, and a protective lab coat. Re-seal container cap tightly immediately after sampling to prevent atmospheric oxidation and caking. Minimize dust generation during weighing and dispensing.