Calculate the [OH−] of a solution with a pH=13.43 at 25 °C .

Question

I keep getting the answer 2.69 x10^-29

Answer 1

Not sure how you got that answer, but here is how to do it.

pH = 13.43

pOH = 14 - 13.43 = 0.57

[OH-] = 1x10^-0.57 = 2.69x10^-1 = 0.269 M

Done another way:

pH = 13.43

[H+] = 1x10^-13.43

[H+] = 3.72x10^-14

[H+][OH-] = 1x10^-14

[OH-] = 1x10^-14 / 3.72x10^-14

[OH- ] = 0.269 M