Question

In the manufacturing of $N{H}_3$, which of the following are favorable conditions?

• A. High pressure and low temperature
• B. High pressure and high temperature
• C. Low pressure and low temperature
• D. Low pressure and high temperature

Answer 1

Answer: (A)

High pressure and low temperature

The manufacturing of ammonia is favored at high pressure and lower temperature.

$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$

This is because, the forward reaction occurs with a decrease in moles from 4 to 2.

Hence, when the pressure is increased, the reaction will proceed in the direction in which the number of moles decreases.

This will lower the pressure and nullify the effect of increased pressure. This happens in the forward reaction. The forward reaction is an exothermic reaction.

When the temperature is lower, the reaction will proceed in the forward direction, so that heat is liberated which will nullify the effect of lower temperature.

Option A is correct.