Question

List the conditions that are required to maximize the yield of ammonia?

Answer 1

Preparation of Ammonia:

• Ammonia can be prepared on a large scale by the use of Haber’s process.
• In this process, Nitrogen and hydrogen react under Optimum conditions to produce Ammonia.
• The reaction for the process can be given as;
  $\underset{\left(\mathrm{Nitrogen}\right)}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Hydrogen}\right)}{3{\mathrm{H}}_2\left(\mathrm{g}\right)}\rightleftharpoons \underset{\left(\mathrm{Ammonia}\right)}{2{\mathrm{NH}}_3\left(\mathrm{g}\right)}$

Conditions required to maximize the yield of ammonia:

• In the Haber’s process, 1 mole of Nitrogen and 1 mole of Hydrogen reacts under Optimum conditions to produce Ammonia. which can be shown as;

$\underset{\left(\mathrm{Nitrogen}\right)}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Hydrogen}\right)}{3{\mathrm{H}}_2\left(\mathrm{g}\right)}\stackrel{450°\mathrm{C},200\mathrm{atm}}{\rightleftharpoons }\underset{\left(\mathrm{Ammonia}\right)}{2\mathrm{N}{\mathrm{H}}_3\left(\mathrm{g}\right)}$

• According to the Le Chatelier’s principle, as the above reaction is exothermic, a low temperature will shift the equilibrium to the right leading to a greater yield of ammonia, hence a temperature of ${450}^{\circ }\mathrm{C}$ will help in maximizing the preparation of ammonia.
• The high pressure on the reaction at equilibrium favors the shift of the equilibrium to the right, as there is a decrease in gaseous moles and thus the pressure of $200\mathrm{atm}$ will maximize the preparation of ammonia.
• To increase the rate of reaction, a catalyst can be used which helps in quickly attaining the equilibrium.
• The reactants Nitrogen and Hydrogen gas should be also made pure to increase the yield of Ammonia.

Hence, above mentioned are the list of conditions that are required to maximize the yield of Ammonia.