Consider the following data concerning the solubility of two gaseous compounds, ammonia and hydrogen chloride, at various temperatures.
Molar Solubility of Gaseous Ammonia and Hydrogen Chloride as a Function of Temperature
|0||52.9 M||22.5 M|
|20||14.8 M||12.3 M|
|60||3.5 M||15.3 M|
The molar solubility of ammonia gas is significantly greater than that of hydrogen chloride at 0ºC, but its solubility drops off dramatically with increasing temperature.
By comparison, raising the temperature causes the molar solubility of hydrogen chloride to decrease at first, but as the temperature gets even higher, the molar solubility of $HCl$ begins to increase.
From experience, we know that the usual pattern is for gaseous solutes become less soluble in water (or other liquid solvents) at elevated temperatures.
Which of the following is the MOST likely explanation for this behavior?