When acid is added to water, it undergoes a process called dilution, where the acid molecules disperse and become less concentrated. This helps in controlling the reaction between the acid and the water, minimizing any potential risks or accidents.
On the other hand, if water is added to concentrated acid, it can cause a violent chemical reaction known as a "heat of dilution" reaction. The sudden mixing of water and concentrated acid generates a lot of heat, which can cause the solution to splatter or even boil, potentially leading to severe injuries.
Therefore, it is crucial to always follow the safety guideline of adding acid to water and never water to acid.
