A buffer solution is made by dissolving H₃PO₄ and NaH₂PO₄ in water. (10.8) b. Write an equation that shows how this buffer neutralizes added base.

Verified step by step guidance

1. Identify the components of the buffer: H₃PO₄ (phosphoric acid) and NaH₂PO₄ (sodium dihydrogen phosphate).
2. Recognize that the buffer system involves the weak acid H₃PO₄ and its conjugate base H₂PO₄⁻.
3. Understand that when a base is added to the buffer, it will react with the weak acid component (H₃PO₄) to minimize pH changes.
4. Write the chemical equation for the reaction between the added base (OH⁻) and the weak acid (H₃PO₄): H₃PO₄ + OH⁻ → H₂PO₄⁻ + H₂O.
5. Note that the reaction consumes the added base (OH⁻) and converts the weak acid (H₃PO₄) into its conjugate base (H₂PO₄⁻), thus maintaining the buffer's pH.

Key Concepts

Buffer Solutions

A buffer solution is a system that resists changes in pH when small amounts of acid or base are added. It typically consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. In this case, H₃PO₄ (phosphoric acid) acts as the weak acid, while NaH₂PO₄ (sodium dihydrogen phosphate) provides the conjugate base.

Neutralization Reaction

A neutralization reaction occurs when an acid and a base react to form water and a salt. In the context of a buffer, when a base is added, the weak acid in the buffer donates protons (H⁺) to neutralize the hydroxide ions (OH⁻) from the base, thus maintaining the pH of the solution.

Equilibrium in Buffer Systems

Buffer systems operate on the principle of chemical equilibrium, where the concentrations of the weak acid and its conjugate base adjust to counteract changes in pH. The equilibrium can be represented by the dissociation of the weak acid, which shifts in response to the addition of a base, ensuring that the pH remains relatively stable despite external changes.