Question

In Haber's process, the ammonia is manufactured according to the following reaction:

$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2{NH}_3\left(g\right);\Delta H^o=-22.4kJ/mol$

The pressure inside the chamber is maintained at $200$ atm and temperature at ${500}^{o}C$. Generally, this reaction is carried out in the presence of $Fe$ catalyst. ${500}^{o}C$ is considered optimum temperature for Haber's process because:

• A. catalyst has maximum activity at this temperature
• B. energy required is easily obtained at this temperature
• C. yield is maximum at this temperature
• D. rate is fast enough while the yield is also appreciable this temperature

Answer 1

The correct option is D rate is fast enough while the yield is also appreciable this temperature

In Haber's process : $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2{NH}_3\left(g\right);{△H}^0=-22.4kJ/mol$ ${500}^{0}C$ is considered as optimum temperature for this reaction because it will provide appreciable amount of yield and also the rate is fast enough from the industrial point of view.

Because at too low temperature it will take a too long time and so is too high as the reaction is exothermic which shifts the reaction backward. So a compromise is made to make the process economical.

Hence, the correct option is $\left(D\right)$.