Chemical Properties

Anhydrous ammonia is easily absorbed by water. At 68°F, about 700 volumes of vapor can be dissolved in one volume of water to make a solution containing 34 percent ammonia by weight. Ammonia in water solution is called aqua ammonia or ammonium hydroxide.

Ammonia, especially in the presence of moisture, reacts with and corrodes copper, zinc, and many alloys. Only iron, steel, certain rubbers and plastics, and specific nonferrous alloys resistant to ammonia should be used for fabrications of anhydrous ammonia containers, fittings, and piping.

Ammonia will combine with mercury to form a fulminate which is an unstable explosive compound.

Anhydrous ammonia is classified by the Department of Transportation as nonflammable. However, ammonia vapor in high concentrations (16 to 25 percent by weight in air) will burn. It is unlikely that such concentrations will occur except in confined spaces or in the proximity of large spills. The fire hazard from ammonia is increased by the presence of oil or other combustible materials.

Anhydrous ammonia is an alkali.

To learn more about Ammonia Refrigeration visit our Ammonia Refrigeration Safety Online Training web page.