Q. While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
The process of dissolving an acid in water is highly exothermic in which a large amount of heat is evolved. It is always recommended that acid should slowly be added to water because evolved heat is easily absorbed by a large amount of water.
If it is done the other way, then it is possible that because of the large amount of heat generated, the mixture splashes out and causes burns,