Very Pure N2 (from barium azide):Ba(N3)2(s) → Ba(s) + 3N2(g)
Haber Process (Industrial synthesis of Ammonia):N2(g) + 3H2(g) ⇌ 2NH3(g) (Conditions: High temp ~700K, High pressure ~200 atm, Catalyst Fe/Mo)
Common Mistakes
Students often confuse reagents for lab preparation vs. industrial preparation of N2.
Don't mix up the products of thermal decomposition, e.g., (NH4)2Cr2O7 yields N2, while NH4NO3 yields N2O.
Students sometimes overlook the inertness of N2 at room temperature and predict reactions readily without considering specific conditions.
Rapid Revision
N2 is prepared in the lab from NH4Cl/NaNO2 or very purely from Ba(N3)2. Industrially, it's from liquid air. Its inertness at room temp is due to the strong N≡N bond. It reacts at high temperatures (e.g., with H2 for NH3, with O2 for NO). Major uses include ammonia synthesis and creating inert atmospheres.
Frequently Asked Questions
How is dinitrogen (N2) typically prepared in the laboratory?▾
In the laboratory, dinitrogen is prepared by heating an aqueous solution of ammonium chloride (NH4Cl) with sodium nitrite (NaNO2). The reaction yields nitrogen gas, sodium chloride, and water.
Why is N2 considered largely unreactive at room temperature?▾
Dinitrogen is unreactive at room temperature due to the presence of a strong triple bond (N≡N) between the two nitrogen atoms. This bond has a very high bond dissociation enthalpy (941.4 kJ/mol), requiring significant energy input to break it.
What are the main industrial applications of dinitrogen?▾
Industrially, dinitrogen is primarily used in the manufacture of ammonia (Haber process), which is a key precursor for fertilizers and nitric acid. It is also used to provide an inert atmosphere in various chemical processes and in cryogenics.
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