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

The dilution of a concentrated acid should always be done by gradually adding concentrated acid to water with stirring, not by adding water to concentrated acid. This is because:

1. When a concentrated acid is added to water to prepare a dilute acid, heat is evolved and is easily absorbed by the large amount of water (to which the acid is being added).
2. However, when water is added to concentrated acid to dilute it, a large amount of heat is evolved at once. This heat rapidly turns some of the water into steam, which can splash the acid onto our faces or clothes and cause acid burns. Even the glass container may break due to excessive heating.