Sodium hydroxide (NaOH)
also known as lye or caustic soda, is commonly used in water treatment to adjust the pH level of water. It is added to water to raise the pH to a neutral level (pH 7) in order to make the water less acidic and less corrosive. Sodium hydroxide also has the ability to remove certain impurities, such as heavy metals, from water. In addition, it can be used to soften hard water by removing calcium and magnesium ions. It is important to use the correct amount of sodium hydroxide and to monitor the pH level of the water to ensure that it is safe for consumption.