What is the ion-product constant, K_w?

1 Answer
Jun 11, 2017

For water, this is the measure of the "autoprotolysis reaction"....

Explanation:

2H_2O(l) rightleftharpoonsH_3O^+ + HO^-

And K_w=[HO^-][H_3O^+]=10^-14 at 298*K.

And when we take -log_10 of both sides we get the useful expression...........

pH+pOH=14, where pH=-log_10[H_3O^+] etc.

How do you think K_w would develop if non-standard conditions pertained; e.g. if temperature was say 373*K. Would K_w remain constant, decrease, increase? Remember that the autoprotolysis reaction as shown is a "bond-breaking reaction".