Final answer:
Oxygen gas solubility decreases as the temperature rises due to increased kinetic energy of the gas molecules, which favors their escape from the solution into the gas phase.
Step-by-step explanation:
The compound whose solubility decreases as temperature increases among the options given is D. Oxygen gas. This phenomenon occurs because gases generally become less soluble in water as the temperature increases. When the water is heated, the kinetic energy of the gas molecules increases, leading to a greater likelihood that the gas molecules will escape into the gaseous phase from the solution. This concept is demonstrated by substances such as HCl, NH₃, and SO₂, and is also true for oxygen gas, which is found in Figure 11.8 showing that the solubility of these gases in water decreases as the temperature increases.