TETRAOXOSULPHATE (VI) ACID is a widely used chemical that almost all manufacturers use directly or indirectly at some stage.
Industrial Preparation of H2SO4
It is widely manufactured by the contact process.
Stages In Contact Process
1. Burning of sulphur in dry air to form sulphur (iv) oxide. S(s) + O2(g) → SO2(g)
2. Purification – The SO formed is passed through electric chamber to remove impurities, which might poison the catalyst to be used and passed through H2SO4 to dry it.
3. Catalyticreaction – in the presence of vanadium (v) oxide (V2O5), the SO2(g) react with oxygen to form sulphur (vi) oxide.
2SO2(g) + O2(g) → 2SO3(g)
4. The formation of Oleum (H2S2O7)).
SO3(g) + H2SO4(g) → H2S2O7(aq)
NB: The SO3 is not dissolved directly in water since the reaction will e too spontaneous and exothermic.
5. Dissolution of oleum –
H2S2O7(aq) + H2O(L) → 2H2SO4(aq)