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Solubility and Temperature for Gaseous Solutes

APCHEM-UH41LT

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

Temperature, $^\circ$C $NH_{3(g)}$ $HCl_{(g)}$
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?

A

Increased kinetic energy of the solvent molecules causes them to become more active and force the gaseous solute particles out of solution.

B

Increased potential energy of the solvent molecules causes them to spread apart more, making space through which the gaseous solute particles can escape.

C

Increased kinetic energy of the gaseous solute molecules results in increased activity and a higher percentage of the solute particles reaching the liquid surface from which they can escape.

D

Increased potential energy of the gaseous solute molecules causes them to spread out and extend outside the boundaries of the solution.