Final answer:
When ∆H∥solution is endothermic, solubility of most solids increases with temperature due to the increased entropy, although solubility of gases like HCl, NH₃, and SO₂ decreases with rising temperatures.
Step-by-step explanation:
When ∆H∥solution is endothermic, the solubility of most solids increases as temperature increases. This relates to the entropy change of the system. As the solid dissolves, the molecules or ions spread into the larger volume of the solution, carrying their thermal energy and thus increasing entropy. For gases like HCl, NH₃, and SO₂, however, solubility decreases with an increase in temperature, because the increased kinetic energy from heating allows the gaseous molecules to overcome attractive forces with the solvent and escape back into the gas phase.
Most solid substances do show increased solubility with rising temperatures, although this effect varies and can be visualized using a solubility curve. The temperature dependence of solubility is a complex interaction of enthalpy and entropy changes, and solubility curves help us to understand and predict these changes.