Answer: The [OH-] of the solution is approximately 5.56 x 10^-5 M, and the pH of the solution is approximately 9.74 at 25 °C.
Step-by-step explanation:
To calculate the [OH-] and pH of a solution with [H+] = 1.8 x 10^-10 M at 25 °C, we can use the relationship between the concentration of hydrogen ions ([H+]) and hydroxide ions ([OH-]) in a water solution at a given temperature:
Kw = [H+] * [OH-]
where Kw is the ion product constant of water, which is equal to 1.0 x 10^-14 at 25 °C.
We are given [H+] = 1.8 x 10^-10 M, and we need to find [OH-] and pH.
Step 1: Calculate [OH-]
Kw = [H+] * [OH-]
1.0 x 10^-14 = (1.8 x 10^-10) * [OH-]
Now, solve for [OH-]:
[OH-] = 1.0 x 10^-14 / 1.8 x 10^-10
[OH-] ≈ 5.56 x 10^-5 M
Step 2: Calculate pH
pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration ([H+]):
pH = -log[H+]
pH = -log(1.8 x 10^-10)
pH ≈ 9.74
Step 3: Check for consistency using Kw
Now, let's check if the calculated values are consistent with the ion product constant of water (Kw):
Kw = [H+] * [OH-]
1.0 x 10^-14 = (1.8 x 10^-10) * (5.56 x 10^-5)
The calculated value for Kw is approximately 1.0 x 10^-14, which is consistent with the ion product constant of water at 25 °C.
Conclusion:
The [OH-] of the solution is approximately 5.56 x 10^-5 M, and the pH of the solution is approximately 9.74 at 25 °C.