Quelle est la différence entre l'ammoniac aqueux et anhydre?


Réponse 1:

Ammoniaisawaterlikesolventthathasanormalboilingpointof33.3[math]°C[/math].Andofcoursetheboilingpointissoelevatedbyreasonofintermolecularhydrogenbonding.Givenatankofammonia,youcanuseammoniaasASOLVENTinwhichtoconductmanyreactions(youneedadryice/EtOH,acetonecondensertocondensetheammoniagas).Andthereactionwithsodiumorpotassiummetals,istrulybeautiful,andtheformationofsolvatedelectronsareobserved,whichhaveavivid,blue,ANDTHENbronzecolour.Ammonia is a water-like solvent that has a normal boiling point of -33.3 [math]°C[/math]. And of course the boiling point is so elevated by reason of intermolecular hydrogen-bonding. Given a tank of ammonia, you can use ammonia as A SOLVENT in which to conduct many reactions (you need a dry-ice/EtOH, acetone condenser to condense the ammonia gas). And the reaction with sodium or potassium metals, is truly beautiful, and the formation of solvated electrons are observed, which have a vivid, blue , AND THEN bronze colour.

33.3-33.3

2NH3(l)NH4++NH22NH_{3}(l) \rightleftharpoons NH_{4}^{+} + NH_{2}^{-}

Dans l'ammoniac pur, l'ammoniac subit une auto-ionisation…

Na(s)+NH3(l)Na+NH2(am)+12H2(g)Na(s) + NH_{3}(l) \rightarrow Na^{+}NH_{2}^{-}(am) + \frac{1}{2}H_{2}(g)

Et avec du métal alcalin….

ASahydrogenbondingsolvent,ammoniahassomesubstantialsolubilityinwater,approx.15molL1.Ammoniaisaweakbaseinwater,andparticipatesintheequilibriumAS a hydrogen-bonding solvent, ammonia has some substantial solubility in water, approx. 15•mol•L^{-1}. Ammonia is a weak base in water, and participates in the equilibrium…

NH3(aq)+H2O(l)NH4++HONH_{3}(aq) + H_{2}O(l) \rightleftharpoons NH_{4}^{+} + HO^{-}

En tant que solvant de liaison hydrogène, l'ammoniac a une solubilité substantielle dans l'eau, env.

15molL115•mol•L^{-1}

. L'ammoniac est une base faible dans l'eau et participe à l'équilibre…

NH3(aq)+H2O(l)NH4++HONH_{3}(aq) + H_{2}O(l) \rightleftharpoons NH_{4}^{+} + HO^{-}

Et l'ammoniac aqueux est couramment utilisé comme solution de nettoyage dans la maison… et vous pouvez le voir par l'arôme assez âcre de l'ammoniac…