How is Cone. `H_(2)SO_(4)` manufactured by contact process ?

Explanation

Sulphuric acid is manufactured by the contact process which involves following steps.
Step- I : Burning of sulphur or sulphide ores in air to generate `SO_(2)`
`S+O_(2)rarrSO_(2)`
Step -II : Catalytic oxidation of `SO_(2)` with `O_(2)` in presence of `V_(2)O_(5)` catalyst gives `SO_(3)`
`2SO_(2)+O_(2)underset(2" bar "720k)overset(V_(2)O_(5))rarr2SO_(3)`
Step - III: `SO_(3)` gas is absorbed in Conc. `H_(2)SO_(4)` to produce oleum. Dilution of oleum with water gives `H_(2)SO_(4)` of desired concentration.
`H_(2)SO_(4)+SO_(3)rarrunderset("Oleum")H_(2)S_(2)O_(7)`
`H_(2)S_(2)O_(7)+H_(2)O rarr2H_(2)SO_(4)`