Calculate the POH of a solution when H+ and PH is given
To calculate the pOH (the negative logarithm of the hydroxide ion concentration) of a solution when the hydrogen ion concentration (H+) or pH is given, you can use the following formulas:
1) If you have the hydrogen ion concentration (H+):
pOH = 14 - pH
For example, if the pH is 3, you can calculate the pOH as follows:
pOH = 14 - 3 = 11
2) If you have the pH:
pOH = 14 - pH
For example, if the pH is 9, you can calculate the pOH as follows:
pOH = 14 - 9 = 5
These formulas are based on the fact that in water, the sum of the pH and pOH is always equal to 14. So, if you know one, you can easily calculate the other.
Once you have the pOH value, you can determine the concentration of hydroxide ions (OH-) using the definition of pOH:
pOH = -log[OH-]
To find OH-, you can rearrange the equation as follows:
[OH-] = 10^(-pOH)
For example, if the pOH is 8, you can calculate the hydroxide ion concentration as follows:
[OH-] = 10^(-8) = 0.0000001 M
Remember that pOH is related to the concentration of hydroxide ions (OH-) in a solution, while pH is related to the concentration of hydrogen ions (H+).