Question

Discuss the theory involved in the manufacture of sulphuric acid by the contact process.

Answer 1

(i) Production of SO₂: 

\[\ce{s + O2 ->[Burn] SO2}\] 

or  \[\ce{4FeS2 + 11O2 ->[raosting] 2Fe2O3 + 8SO2}\]

(ii) Oxidation of SO₂ to SO₃:

\[\ce{2SO2 + O2 <=>[V2O5, 2 atm.][1075 K] 2SO3 + Heat energy}\] 

(iii) Conversion of SO₃ into H₂SO₄:

\[\ce{SO3 + \underset{(conc)}{H2SO4}->\underset{(Oleum)}{H2S2O7}}\]

\[\ce{H2S2O7 + H2O -> 2H2SO4}\]