Final answer:
To calculate the pH of a solution with a hydroxide ion concentration of 1 × 10^-4 M, you first use the water dissociation constant to find the hydronium ion concentration and then take the negative logarithm of that concentration to determine the pH. The pH is 10.0, which is the answer to the question.
Step-by-step explanation:
The question asks for the pH of a solution when the hydroxide ion concentration ([OH-]) is given. To find the pH from the [OH-], we first need to calculate the concentration of hydrogen ions ([H3O+]) using the water dissociation constant (Kw) which is 1.0 × 10-14 at 25 °C. The calculation is as follows:
[H3O+] = Kw / [OH-] = 1.0 × 10-14 / 1 × 10-4 = 1.0 × 10-10
Next, we calculate the pH:
pH = − log [H3O+] = −log(1.0 × 10-10) = 10
Therefore, the pH of a solution with [OH-] = 1 × 10-4 M is 10.0, which corresponds to option A. 10.0.