formula

Molecular formular of sulphuric acid(硫酸) is H2SO4. It is formed by contact process.
1. S(s) + O2(g) ----------->SO2(g)
2. 2SO2(g) + O2(g)----------->2SO3(g) ( use V2O5 as a catalyst)(reversible reaction)
3. SO3(g) + H2O(l)----------->H2SO4(l)
但因為3.係highly exothermic
so通常會form oleum(H2S2O7)先
3. SO3(g) + H2SO4(l)------->H2S2O7(l)
4. H2S2O7(l) + H2O(l)------>2H2SO4(l)

Hope that I can help you!!

H2SO4

H2SO4