Calculate the pH of each solution given the following:

c. [OH⁻] ...

Question

Calculate the pH of each solution given the following:

c. [OH⁻] = 1 x 10⁻⁵ M

Accepted Answer

Hey, everyone. We're asked to give the P H of a solution if the concentration of hydroxide ions with a formula of O H minus in the solution is 5. times 10 to the negative four molar. Now, in order to calculate our P H, we first need to find the concentration of our hydrogen ions since our P H is equal to the negative log of the concentration of our hydro ion. And we can do so by rearranging the water dissociation expression, which is our K W. And we know that our K W is equal to the concentration of our hydro ion times the concentration of our hydroxide ion. And this is going to be equal to 1.0 times 10 to the negative rearranging this equation to solve for the concentration of our hydro num ion, we end up with 1.0 times 10 to the negative divided by the concentration of our hydroxide ion. So plugging in our value, we get 1.0 times 10 to the negative 14 divided by the concentration of our hydroxide ion which is 5.33 times 10 to the negative four molar. So when we calculate this out, we end up with a concentration of 1.88 times 10 to the negative 11 molar, which is our concentration of our hydro num ion. Now to calculate our P H, we're going to take the negative log of our concentration of hydro num ion which is 1.88 times 10 to the negative 11 molar. So when we calculate this out, we end up with a P H of 10.726. And as we've learned, the number of decimal places in our P H will be equivalent to the number of significant figures in our concentration. So for this question, we see three significant figures. So our P H needs to have three decimal places in our final answer. So our final answer for our P H is 10.726. Now, I hope this made sense and let us know if you have any questions.

Calculate the pH of each solution given the following: c. [OH⁻] = 1 x 10⁻⁵ M

Watch next