The pH of concentrated sodium hydroxide is 14. It is one of the most strongly basic substances that exists; however, it is rarely encountered in its fully concentrated form, and its pH in solution depends on its concentration.
Sodium hydroxide, also known as caustic lye or simply caustic, is a commonly encountered industrial agent. It has applications both in neutralizing acidic waste and in the creation of soaps from plant and animal fats. Its extreme pH makes it hazardous to handle, and it can cause severe chemical burns and eye damage if mishandled. The danger of skin corrosion exists at any concentration above 2 percent.