How does a higher temperature affect the pH of a solution?

When the temperature of a solution increases, the ion product of water, denoted as Kw, also increases. This is because the dissociation of water into hydrogen ions (H⁺) and hydroxide ions (OH⁻) is an endothermic process. As the temperature rises, more water molecules have the energy required to break apart, resulting in a greater concentration of both H⁺ and OH⁻ ions.

As Kw increases with temperature, the concentrations of H⁺ and OH⁻ ions in pure water will also increase. However, the pH is defined as the negative logarithm of the concentration of H⁺ ions; thus, an increase in H⁺ ion concentration at a higher temperature will lead to a decrease in pH. Since pOH is also related to the concentration of hydroxide ions (OH⁻) and is connected to Kw through the relationship pH + pOH = 14 (under standard temperature conditions), an increase in Kw results in a lower pOH as well. Therefore, the rise in Kw contributes to a decrease in both pH and pOH values as the temperature increases.

This relationship highlights how temperature directly influences the behavior of ion concentrations in an aqueous solution, altering both p