The document discusses pH and how it is affected by temperature. pH is a measure of how acidic or basic a solution is, ranging from 0-14 with 7 being neutral. It explains how pH is impacted by concentrations of hydrogen (H+) and hydroxide (OH-) ions in water and how temperature influences these ion concentrations. Specifically, increasing the temperature causes an increase in the ion product of water and a decrease in pH. Three key effects of temperature on pH are summarized.