Sodium Nitrite

· Sodium nitrite ( Na₂NO₂ ) is commonly used for coloring and preserving fish, meat , and other foods. Pure sodium nitrite is a white to pale yellow crystal. It has excellent water solubility and hygroscopicity ; its aqueous solution is weakly alkaline with a pH of approximately 9. It is readily soluble in liquid ammonia and slightly soluble in organic solvents such as ethanol , methanol , and ether . In air, sodium nitrite is slowly oxidized to sodium nitrate ( Na₂NO₃ ), which is a strong oxidizing agent . Sodium nitrite is prone to explosion upon contact with organic matter.

Sodium nitrite has a wide range of uses, mainly as a food preservative and color-protecting agent (to keep meat products bright red and inhibit Clostridium botulinum), an intermediate in the production of azo dyes and other products in dye and organic synthesis , a vasodilator and liver function test in the pharmaceutical field , a corrosion inhibitor and heat treatment agent in metal processing , and an important chemical intermediate in the rubber and textile industries.