Final answer:
When the concentration of hydroxide ions ([OH-]) is 3.3 x 10^-9 M, the concentration of hydronium ions ([H3O+]) can be found using the ion product of water, resulting in a [H3O+] of 3.0 x 10^-6 M.
Step-by-step explanation:
To find the concentration of hydronium ions ([H3O+]) when the concentration of hydroxide ions ([OH-]) is given, you can use the product of their concentrations, which is always equal to 1.0 × 10-14 at 25°C (298 K). This relationship is represented by the equation:
[H3O+] × [OH-] = 1.0 × 10-14
Given that [OH-] = 3.3 × 10-9 M, you can rearrange the equation to solve for [H3O+]:
[H3O+] = × 10-14 / [OH-]
[H3O+] = 1.0 × 10-14 / 3.3 × 10-9
[H3O+] = 3.03 × 10-6 M
Therefore, the correct answer is:
A. 3.0 × 10-6 M