pOH, or potential of hydroxide ion, is a measure of the hydroxide ion (OH–) concentration in a solution. It quantifies the alkalinity or basicity of a solution.
Understanding pOH
pOH is a scale used to determine the hydroxide ion (OH–) concentration in a solution. The pOH value is calculated using the following formula:
pOH = -log[OH–]
Where [OH–] represents the hydroxide ion concentration in moles per liter (M).
Relationship Between pH and pOH
pH and pOH are related by the following equation:
pH + pOH = 14 (at 25°C)
This relationship highlights that as pH increases (more basic), pOH decreases (less basic), and vice versa. Understanding this relationship is crucial in determining whether a solution is acidic, neutral, or basic.
Examples
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Example 1: Calculating pOH: If a solution has a hydroxide ion concentration of 1.0 x 10-5 M, the pOH would be:
pOH = -log(1.0 x 10-5) = 5
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Example 2: Determining pH from pOH: If a solution has a pOH of 3, the pH would be:
pH = 14 - pOH = 14 - 3 = 11
Applications
- Environmental Monitoring: pOH can be used to assess water quality and determine the level of alkalinity.
- Industrial Processes: Many industrial processes require precise control of pOH to optimize reactions and prevent corrosion.
- Laboratory Research: pOH measurements are essential for various chemical and biological experiments.
