Liquid (anhydrous) ammonia, NH3(l), with a boilingpoint of –33 °C, is often used as an alternate solvent to water. Itforms strong hydrogen bonds and the polar molecules can solvateionic compounds. Anhydrous ammonia also undergoes autoionization.Therefore, there can be acidic, neutral, or basic species insolutions of liquid ammonia.
a) Write the chemical equation, using the Brønstedâ€Lowryperspective, that describes the autoionization of NH3(l).(Hints: for water this equation is 2H2O(l) ⇌ H3O+(aq) + OH–(aq);X(am) denotes a solute solvated by ammonia)
b) Identify the species in pure NH3(l) that can act asBrønsted acids and as Brønsted bases. (There are more than one foreach case.)
c) Write the equilibrium expression for the autoionizationconstant Kam of liquid ammonia.
d) At ï€50°C, the autoionization constant of ammoniaKam is 10ï€30. What are the conditions for“neutralâ€,
“acidicâ€, and “basic†liquid ammonia solutions at ï€50°C?
e) Propose a quantity, analog to the pH, that indicates theacidity of a liquid ammonia solution.
f) For each of these compounds: NH4Cl, LiNH2, KOH, N(CH3)3, whendissolved in liquid ammonia, identify whether it gives rise to an\"acidic\" solution or a \"basic\" solution. Write out the chemicalequilibrium that shows how it behaves as an acid or a base inNH3(l).
