Question

why should water be never added dropwize

to concentrated H2 s o4

Answer 1

water should never added to sulphuric acid as heat evolved which might harm the person addind the water

Answer 2

This is because the reaction between acid and water is highly exothermic and thus it produces heat when water is added to acid, it results in vigorous boiling of the solution and the amount of heat produced is enormous so it splashes the acid out of the containers which can result in acid burns.