What is the correct procedure for mixing acid and water?

Adding acid to water is the correct procedure because it helps to minimize the risk of exothermic reactions. When acid is mixed with water, the dilution of the acid allows for the release of heat to be absorbed by the larger volume of water, which reduces the likelihood of violent reactions that can occur if water were added to concentrated acid. This approach ensures that the reaction is controlled and that the resulting heat does not cause splattering or boiling, which can be dangerous.

It is crucial to always remember that when handling corrosive substances like acids, proper safety precautions should be taken, including wearing appropriate personal protective equipment. The recommended sequence—acid to water—enhances safety in laboratory or practical settings.