The operating temperature range for the Haber process is $350-500^{\circ}C$. It is used for the production of ammonia at
- $20 \:MPa$ using $Fe$ catalyst in an exothermic reaction
- $0.1 \:MPa$ using $Fe$ catalyst in an exothermic reaction
- $20 \:MPa$ using $Fe$ catalyst in an endothermic reaction
- $20 \:MPa$ using zeolite catalyst in an endothermic reaction
