\[pOH=-\log_{10}[OH^-]\]
Variables
pOHpotential of hydroxide
OH[OH⁻]hydroxide ion concentration (mol/L)
Description
What is this formula?
This formula calculates pOH from the hydroxide ion concentration. The pOH scale is a logarithmic measure of the basicity or alkalinity of a solution.
When to use it
Use this formula when the hydroxide ion concentration is known and the alkalinity of the solution needs to be expressed on the pOH scale.
Example
A solution has:
[OH⁻] = 1.0×10⁻² mol/L
Formula:
pOH = -log10([OH⁻])
Substitution:
pOH = -log10(1.0×10⁻²)
Result:
pOH = 2.00
The solution is strongly basic.
Applications
- Acid-base chemistry
- Water treatment
- Environmental monitoring
- Industrial process control
- Laboratory analysis
- Chemical education
Note
The pOH scale is logarithmic. A change of one pOH unit corresponds to a tenfold change in hydroxide ion concentration. At 25°C, pH and pOH are related through pH + pOH = 14.