The ionization of water is endothermic. How is Kw related to the temperature of water?

Question

A. Kw increases as temperature increases 

B. Kw decreases as temperature increases 

C. Kw increases as temperature decreases 

D. Kw remains constant as temperature  decreases

Answer 1

Since it is endothermic, you can write heat as a reactant.

Heat + H₂O <==> H⁺ + OH^-

As the temperature increases, ionization increases producing more product (Le Chatelier)

Kw = [H+][OH-]

So, Kw increases as the temperature increases.  ANS A