Give the principle of contact process for the manufacture of sulphuric acid.Give an equation to show oxidising property of sulphuric acid.

Principle of contact process-
The process of manufacture of sulphuric acid is known as contact process.It is manufacture from sulphur trioxide,SO₃.This sulphur trioxide is formed by the oxidation of sulphur dioxide,SO₂.The steps involved in the process are as follows-
1. S + O₂ --------------> SO₂
2. 2SO₂ + O₂ ------------> 2SO₃
The key step in the manufacture of sulphuric acid is the above step which involves the oxidation of SO₂ to SO_3,which is a slow,reversible and exothermic reaction.To increase the rate of attainig the equilibrium,a catalyst called divanadium pentaoxide V2O5 is used at a pressure of 2 atm and a temperature of about 700K.The pressure should be low and temperature must be high so as to obtain the maximum yield os SO_3.
This SO₃ is passed through the sulphuric acid to obtain oleum,H₂S₂O_7.Dilution of which gives H₂SO_4.
3. SO₃ + conc.H₂SO₄ -----------> H₂S₂O₇
4.H₂S₂O₇ + H₂O ------------------> 2H₂SO₄
Oxidising property of H2SO4-
Cu + 2H₂SO₄ ----------------> CuSO₄ + SO₂ + 2H₂O