A solution with a pH of 2.50 has an [OH^-] of ________

Question

Quizplus · Accepted Answer

The formula for [OH-] is 10^-pH. 
Substituting pH = 2.50 in the above formula, we get [OH-] = 10^-2.50 = 3.16 x 10^-3.
Using the formula for [H+] and [OH-] concentration in water, we get,
Kw = [H+][OH-] = 1 x 10^-14
Substituting the values, we get,
1 x 10^-14 = [H+][3.16 x 10^-3]
[H+] = 1 x 10^-14 / 3.16 x 10^-3 = 3.16 x 10^-12
The concentration of [OH-] in the solution can be found using the formula [OH-] = Kw / [H+]
[OH-] = 1 x 10^-14 / (3.16 x 10^-12) = 3.16 x 10^-3
Therefore, the answer is B.

A Solution with a PH of 2 ×\times× 102 ×\times× 10-12 ×\times× 10-3 ×\times×

A Solution with a PH of 2 $\times$ 10² $\times$ 10^-12 $\times$ 10^-3 $\times$