Usually a hydroxide of lithium, sodium, potassium, rubidium or cesium, but also the carbonates of these metals, ammonia, and the amines. (Grant & Hackh's Chemical Dictionary, 5th ed)
Solutions with a pH range between 7.1 to 14.0. An alkali is corrosive when pH is higher than 11.5. See also pH. Uses: Many cleaning products (e.g., bleach, detergents, dishwashing soaps, drain openers and oven cleaners) are alkalies.