The 20% potassium hydroxide solution is a highly concentrated alkaline solution used in various areas of the laboratory and industry. In microbiology, it can be used to distinguish yeasts and filamentous fungi by soaking samples in the solution and then examining them microscopically. The high concentration ensures rapid and effective separation of organisms.

In the chemical industry, 20% potassium hydroxide is used in the manufacture of soaps, detergents and other products that require a strong alkaline reaction. In the textile industry, it can be used to remove grease and dirt, while in the food industry it is used to regulate pH and as a preservative.

In the laboratory, 20% potash lye is used as an etchant to remove proteins and grease from glassware or to neutralize acids. In industry, it is used in anisotropic etching of silicon and as an electrolyte. In addition, potassium hydroxide is used as an etching additive in metallography to make certain structures in metals visible. The 20% concentration provides a very effective etching reaction, with the reaction rate being faster than at lower concentrations.