Chapter 13, Problem 118A

Interpretation Introduction

Interpretation:

The effect of pressure and temperature on percent yield of ammonia is to be explained.

Concept introduction:

This is based on concept of equilibrium and Le-Chatlier’s principle.

According to Le-Chatlier’s principle,

Exothermic reactions are favored by decrease in temperature and endothermic reactions are favored by increase in temperature.

Increase in pressure shifts the reaction towards the direction which contains less number of gaseous moles and vice-versa.

Answer to Problem 118A

The production of ammonia is favored by low temperature and high pressure.

Explanation of Solution

Haber’s process is given by:

${\text{N}}_{\text{2}}{\text{+3H}}_{\text{2}}\to {\text{2NH}}_{\text{3}}\text{+heat}$

Thus haber process is exothermic and proceed by decrease in number of gaseous moles.

Therefore it is favored by high pressure and low temperature.

Conclusion

Decreasing the temperature and increasing the pressure increases the percent yield of ammonia.