An alkali is a basic ionic compound of an alkali earth metal or alkali metal element. Alkalies are most noted for their ability to neutralize or balance acidity. An alkali solution turns a red litmus paper blue. Caustic soda is a good example of an alkali.
Alkalies are known for being basic compounds that dissolve in water. They have a pH greater than 7. They turn phenolphthalein indicator from colorless to pink. Alkali solutions are soapy or slippery to touch. Due to their caustic properties, they cause severe burns or corrosion when concentrated. When an alkali solution mixes with an acid, there is always a formation of a salt.
Encyclopædia Britannica explains that some stages of alkali are used frequently in consumer goods. Soda ash and caustic soda are industrially manufactured alkali, and they are used to make: glass, soap, miscellaneous chemicals, rayon, cellophane, paper, pulp, aluminum and other metals, cleansers, detergents, textiles, water softeners, bicarbonate of soda, gasoline and other forms of fuel. Other manufactured alkali include potassium hydroxide, potash and lye.