A solution of potassium hydroxide is in equilibrium with undissolved solute at 45°C. What will happen if the temperature is raised to 50°C? (ΔH_soln = -57.6 kJ/mol) A) The mass of undissolved KOH will increase. B) The mass of undissolved KOH will decrease. C) The mass of undissolved KOH will be unchanged. D) The mass of water in the solution will increase. E) The entropy of the system will decrease.

Question

Quizplus · Accepted Answer

The negative value of ΔH_soln indicates that the dissolution of KOH in water is exothermic, meaning that the process releases heat. According to Le Chatelier's principle, when the temperature is increased, the equilibrium will shift in the direction that absorbs heat, which in this case is the reverse reaction of KOH dissolving in water. Therefore, the mass of undissolved KOH will decrease, and more KOH will dissolve in the solution.

A Solution of Potassium Hydroxide Is in Equilibrium with Undissolved