Question
Why the manufacture of H2SO4 from SO3 in the presence of a catalyst is called a contact process? Why catalysts are taken in powdered form?
Answer
The manufacture of H2SO4 from SO3 in the presence of a catalyst is called a contact process because the reaction between SO2 and O2 takes place on the surface of a catalyst, and the reactants make only brief contact with the catalyst. This process occurs in a series of chambers or containers, and the gases “contact” the catalyst on their way through each chamber.
Catalysts are taken in powdered form to maximize their surface area and increase the number of active sites available for the reaction to occur.