Alkaline materials are bases in chemistry, meaning they are able to neutralize acids. The pH of an alkaline material dissolved in water is above 7 because these materials have a relatively low concentration of hydrogen ions.
Alkaline materials give water a slippery feel on the fingers because of a chemical reaction with the oils on the skin. This same reaction transforms animal fat into soap through the addition of lye. In high concentrations, alkaline materials are caustic. They are bitter tasting.
Many alkaline compounds lower the pH of a material by providing OH- ions in a solution. OH- is composed of an oxygen atom bonded to a hydrogen atom and is known as a hydroxide. Sodium hydroxide, NaOH, dissociates in water to turn into Na+ ions and OH- ions. However, some alkalines, such as ammonia NH3, reduce pH by binding hydrogen ions, forming NH4+ ions and OH- ions in solution.
Alkaline materials are used in many different industries. Farmers often apply anhydrous ammonia to their soil to provide nitrogen, an important plant nutrient. In paper manufacturing, sodium hydroxide digests wood pulp to provide the fiber to make paper. It is also essential in the manufacturing of rayon. In the home, magnesium hydroxide is in medicine to counteract stomach acids. Sodium carbonate, also known as washing soda, is used to boost the power of ordinary detergents. Sodium bicarbonate is baking soda, which helps baked goods rise.