Optimal Conditions: Pressure ~200 atm, Temperature ~700 K (450-500 °C).
Catalyst: Finely divided iron (Fe), with molybdenum (Mo) acting as a promoter.
Structure: Pyramidal geometry, sp³ hybridization, bond angle ~107° due to lone pair repulsion.
Properties: Colourless gas, pungent smell, highly soluble in water (forms NH₄OH, a weak base).
Nature: Lewis base (due to lone pair donation), proton acceptor (Brønsted-Lowry base).
Must-Know Formula / Reaction
Haber's Process for Ammonia Synthesis:
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
N₂: Nitrogen gas (reactant)
H₂: Hydrogen gas (reactant)
NH₃: Ammonia gas (product)
ΔH = -92.4 kJ/mol: Indicates an exothermic reaction, releasing heat.
Conditions: Catalyst (Fe/Mo), High Pressure (200 atm), Moderate Temperature (700 K).
Common Mistakes
Students often confuse the theoretical thermodynamic conditions (low T, high P for max yield) with practical optimal conditions (moderate T for catalyst activity).
Don't confuse the roles of iron (catalyst) and molybdenum (promoter); Fe speeds up the reaction, Mo enhances Fe's activity.
Misinterpreting ammonia's basic nature; it's a base because of its lone pair of electrons, not the presence of hydroxide ions in its formula.
Rapid Revision
Ammonia (NH₃) is synthesized via the Haber process using N₂ and H₂ under specific conditions (Fe/Mo catalyst, ~200 atm, ~700 K). It has a pyramidal structure with sp³ hybridization due to a lone pair on nitrogen, making it a Lewis base and a key reagent in many reactions.
Frequently Asked Questions
What are the optimal conditions for the Haber process?▾
The optimal conditions for the Haber process involve a pressure of approximately 200 atmospheres and a temperature around 700 K (450-500 °C). Finely divided iron acts as the catalyst, and molybdenum serves as a promoter to enhance its efficiency.
Why is ammonia considered a Lewis base?▾
Ammonia (NH₃) is considered a Lewis base because the nitrogen atom possesses a lone pair of electrons. It can readily donate this lone pair to an electron-deficient species (a Lewis acid), forming a coordinate covalent bond.
What is the geometry and hybridization of ammonia?▾
The nitrogen atom in ammonia undergoes sp³ hybridization. Due to the presence of three bond pairs and one lone pair of electrons, the molecule adopts a pyramidal geometry, with a bond angle slightly less than the ideal tetrahedral angle (approx. 107°).
Practice MCQs on this topic
Interactive questions with instant AI explanations