Which of the following accounts for the observation that th

. Which of the following accounts for the observation that the pH of pure water at 0°C is 7.5? (A) At 0°C water is naturally alkaline. (B) At 0°C the autoionization constant for water, Kw, is smaller than it is at 25°C. (C) At 0°C water has a lower density than it does at 25°C, therefore, [H\'] is lower. (D) At 0°C water ionizes to a greater extent than it does at 25°C.

Solution

B is the correct option.as ionization of water is exothermic reaction.hence as we decrease the temperature Kw will decreases and cause lesser amount of H+