Potassium hydroxide pellets absorbing water in a petri dish. This has caused the pellets to dissolve. Potassium hydroxide is a hygroscopic (absorbs water readily) compound that dissolves exothermically (produces heat) in water. It is very alkaline and is used in agriculture to correct the pH of acidic soils. Potassium hydroxide is corrosive, causing serious burns to the skin and eyes if it comes into contact with those areas.