What is the pH of a 1.00 x 10^-4 M solution of lithium hydroxide solution?

1 Answer
Sep 6, 2016

pH=10

Explanation:

pH, "pouvoir hydrogene", =-log_10[H_3O^+]

Now it is a fact that in water the following autoprotolysis takes place:

2H_2O(l) rightleftharpoonsHO^(-) + H_3O^+

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

If we take -log_10 of both sides we get:

pK_w =14=-log_10[H_3O^+]-log_10[HO^-]

But by definition, pH =-log_10[H_3O^+] and pOH =-log_10[HO^-]

Thus pK_w =14=pH+pOH

And so pOH = -log_10(10^-4) = 4

And pH=10.

Capisce?