Discuss the application of Lechateliers principle for the industrial synthesis of NH₃ and SO₃.

a) Industrial synthesis of ammonia:
$\underset{\left(\mathrm{g}\right)}{{\mathrm{N}}_2}+\underset{\left(\mathrm{g}\right)}{3{\mathrm{H}}_2}\rightleftharpoons \underset{\left(\mathrm{g}\right)}{2{\mathrm{NH}}_3};\mathrm{\Delta H}=-92.3\mathrm{KJ}$
Effect of temperature: Formation of ammonia is exothermic reaction. Hence at low temperature is favourable for greater yield of NH₃. But at low temperature reaction between
N₂ and H₂ is very slow. Therefore an optimum temperature of 725 – 775K is used.
Effect of pressure: The formation of ammonia is accompanied with decrease in volume. So high pressure is favourable for higher yield of NH3. Hence 200 – 300 atm pressure is used.
Optimum conditions:
Concentration: pure N₂ and H₂ should be mixed in high concentration.
Temperature: 725 – 775 K
Pressure: 200 – 300 atm
Catalyst: Finely divided iron
Promoter: Mo
b) Industrial synthesis of SO₃ :
$\underset{\left(\mathrm{g}\right)}{2{\mathrm{SO}}_2}+\underset{\left(\mathrm{g}\right)}{{\mathrm{O}}_2}\rightleftharpoons =\underset{\left(\mathrm{g}\right)}{2{\mathrm{SO}}_3};\mathrm{\Delta H}=-189\mathrm{KJ}/\mathrm{mol}$
Effect of temperature: Formation of SO₃ is exothermic reaction. Low temperature favours for greater yield of SO₃. But at low temperature reaction is very slow. Hence optimum temperature of 673K is used.
Effect of pressure: The formation of SO₃ is accompanied with decrease in volume hence high pressure is favourable for the formation of SO₃. So optimum pressure of 1.5 to 1.7 atm
is used.
Optimum conditions:
Concentration: High concentration of SO₂ and O₂
Temperature: 673 K
Pressure: 1.5 – 1.7 atm
Catalyst: V₂O₅