Question

While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

Answer 1

While diluting an acid, the acid should always be added slowly to water with constant stirring and in small amounts. The dilution of an acid is an exothermic reaction. So, when we add acid to water, the evolved heat gets absorbed by the water that is in bulk. But when we add water to acid, a large amount of heat is evolved, the water turns into vapour and the acid splashes onto our clothes or face, causing severe burns.