pH

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Topics > Acids & Bases > pH

Definition: pH is a scale used to measure the acidity or basicity of an aqueous (water-based) solution.The term "pH" stands for "potential of Hydrogen" or "power of Hydrogen."

The pH Scale

Range: The pH scale typically ranges from 0 to 14.

- Acidic Solutions: pH less than 7.
- Neutral Solutions: pH equal to 7.
- Basic (Alkaline) Solutions: pH greater than 7.

Each value represents a tenfold difference in hydrogen ion concentration.

Understanding Hydrogen Ion Concentration

pH and Hydrogen Ions: pH is a measure of the concentration of hydrogen ions (H⁺) in a solution.
Formula: pH = -log[H⁺], where [H⁺] is the concentration of hydrogen ions in moles per liter (M).

pH and pOH

pOH: Similarly, pOH is the measure of hydroxide ion (OH⁻) concentration.
Relation: pH + pOH = 14 (at 25°C). This shows the inverse relationship between hydrogen and hydroxide ions.

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