Sulfuric acid can be produced by dry distillation of iron sulfate heptahydrate, copper sulfate pentahydrate. When these compounds were heated they decompose to form iron and copper oxides eliminating water and sulphur trioxide which combine together to form dilute solution of sulphuric acid. It is suitable as dehydrating agent, catalyst, active reactant in chemical industry. It is also suitable to control pH of saline solutions to strong fuming acids.