The pH is given for three solutions. Calculate [H+] and [OH -] in each solution.

Question

a) pH = 2.45

[H⁺]

 M

[OH^-]

 M

(b) pH = 12.42

[H⁺]

 M

[OH^-]

 M

(c) pH = 6.29

[H⁺]

 M

[OH^-]

 M

Answer 1

I will show you how to do the first one, and then you should be able to do the other ones.

pH = - log [H+]

log [H+] = -pH

Find the antilog of - pH on your calculator.

The [OH-] concentration is then 10^-14 / [H+]

For the first problem, log [H+] = -2.45.

antilog of -2.45 = 3.55 x 10^-3 M

[OH-] = 10^-14 / 3.55 x 10^.3 = 2.82 x 10^-12 M

You should be able to finish the rest.