Write the conditions to maximise the yield of `H_2SO_4` in contact process.

Explanation

Ans: The key reaction in the manufacture of .H_i SO_4. by contact process is the conversion of .SO_2. into .SO_y^*.
.2 SO_2~g+O_2^*~g 2 SO_3~g Delta_, H^circ=-196.6 ~kJ ~mol^-1.
The reaction is i reversible ii exothermic iii proceeds with a decrease.in volume.
.because. Low temperature and high pressure are the favourable conditions for maximum yield. But the temperature should not be very low, otherwise rate of reaction will become slow.
In practise the plant operated at 720K and a pressure of 2 bar. A catalyst of V_2 O_5 is used to speed up the reaction