Q.Mention three areas in which H2SO4 plays an important role.

Sulphuric acid, $H_2SO_4$, is manufactured industrially by the Contact process: sulphur or sulphide ores are burned to $SO_2$, which is catalytically oxidised to $SO_3$ over a $V_2O_5$ catalyst at about 720 K and 2 atm pressure, conditions chosen to maximise the yield of the exothermic, mole-decreasing equilibrium $2SO_2 + O_2 \rightleftharpoons 2SO_3$ (moderate temperature to favour the exothermic forward reaction without sacrificing rate, and modest excess pressure with excess air/oxygen to push the equilibrium towards $SO_3$); the $SO_3$ is then absorbed in concentrated $H_2SO_4$ to give oleum, which is diluted with water to the required strength. Sulphuric acid is one of the most important industrial chemicals, used in the manufacture of fertilizers (such as superphosphate and ammonium sulphate), in petroleum refining, in the manufacture of pigments, p …