Question

Which type of behaviour is expected on adding water to sulphuric acid?

Answer 1

When water is added to concentrated sulphuric acid, the process is highly exothermic because strong interactions form between water and sulphuric acid molecules. This leads to a large release of heat, and the solution shows negative deviation from ideal behaviour (i.e., `Delta H_"mixing" < 0)`.

Due to the intense heat, adding water to acid can cause violent boiling and splashing, which is dangerous.

Hence, for safety, acid should always be added to water and not water to acid, as the latter can cause violent splashing.