Water autoionizes to produce hydronium ion and hydroxide ion. The product of the concentrations of these ions equals the water autoionization constant, Kw. This ionization constant depends on temperature, the enthalpy change, and the entropy change associated with the reaction. Because the enthalpy change of this reaction is _____, the pH of pure water _____ with decreasing temperature.
A) positive, increases
B) positive, decreases
C) negative, increases
D) negative, decreases
E) zero, does not change