Phosphate Buffer System
H2PO4− ⇌ HPO42− + H+
Overview
The dihydrogen phosphate/hydrogen phosphate buffer system operates near pH 7.2, making it ideal for biological applications. With pKa2 = 7.2, it buffers effectively between pH 6.2 and 8.2. This is the buffer system used in phosphate-buffered saline (PBS), the most common buffer in biology.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Phosphoric Acid H₃PO₄ | 1 | (aq) |
Everyday Example
Phosphate buffers help maintain the pH of many biological fluids and are used in nearly every molecular biology laboratory.
Industrial Importance
The phosphate buffer system is used in PBS for cell culture, in clinical diagnostics, in food processing, and in pharmaceutical formulations requiring near-neutral pH.
Properties
- Type
- Acid-Base
- Reversible
- Yes
- Energy
- Endothermic
Related Reactions
Acetic Acid and Sodium Acetate Buffer System
Acetic Acid and Sodium Hydroxide Neutralization
Acetic Acid Dissociation in Water
Aluminum Chloride and Chloride Ion (Lewis Acid-Base)
Aluminum Hydroxide as Amphoteric Acid with NaOH
Aluminum Hydroxide as Amphoteric Base with HCl
Ammonia and Ammonium Chloride Buffer System
Ammonia and Hydrochloric Acid
Ascorbic Acid and Sodium Hydroxide
Barium Hydroxide and Ammonium Thiocyanate (Endothermic)
Frequently Asked Questions
What is the equation for Phosphate Buffer System?
The balanced equation is: H₂PO₄⁻ ⇌ HPO₄²⁻ + H⁺.
What type of reaction is Phosphate Buffer System?
Phosphate Buffer System is a acid-base reaction. It is reversible under certain conditions.
Is Phosphate Buffer System exothermic or endothermic?
Phosphate Buffer System is endothermic (absorbs energy).