pH plus pOH Relationship

Comes from taking the negative log of Kw. Lets you find pOH (and hence hydroxide concentration) once pH is known.

$$\mathrm{pH}+\mathrm{pOH}=14(\text{at }25^{\circ }\mathrm{C})$$

Variables

Symbol	Meaning	Unit
$\mathrm{pH}$	Negative log of hydrogen-ion concentration	dimensionless
$\mathrm{pOH}$	Negative log of hydroxide-ion concentration	dimensionless

Worked example

If pH = 3, then pOH = 11. If pH = 10, then pOH = 4.

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Part of The Blueprint of Water