Alkali

(al'-ka-li). The term includes the hydrated oxids of the alkali metals; these are electro-positive, are strong bases, uniting with acids to form salts, turn red litmus blue, and saponify fats. A., Caustic (usually potash), when so concentrated as to po e caustic properties; potash and Soda are called fixed alkalies, because permanently solid; soda is called a mineral, potash a vegetable, and ammonia a volatile alkali.