Question

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

Answer 1

Theory of contact process : 

(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 :

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

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