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What is the difference between buffer capacity and buffer effectiveness?
Buffer capacity is the amount of acid or base a buffer can neutralize. Buffer effectiveness is how well the buffer resists pH changes.
Compare how strong acids/bases and weak acids/bases affect buffer formation.
Strong acids/bases do NOT form buffers with their conjugates because their conjugates are too weak. Only weak acid/base pairs can create buffers.
How does a buffer neutralize added acid (H+)?
The conjugate base (A-) reacts with H+ to form the weak acid (HA), preventing a large increase in [H+].
How does a buffer neutralize added base (OH-)?
The weak acid (HA) reacts with OH- to form the conjugate base (A-) and water (H2O), preventing a large increase in [OH-].
What are the steps to preparing a buffer solution?
- Choose a weak acid/base system with a pKa close to the desired pH. 2. Mix the weak acid/base with its conjugate in comparable concentrations. 3. Adjust the pH with strong acid or base, if necessary.
What is the effect of adding a strong acid to a buffer solution?
The conjugate base in the buffer reacts with the added acid, minimizing the change in pH.
What is the effect of adding a strong base to a buffer solution?
The weak acid in the buffer reacts with the added base, minimizing the change in pH.
What happens if the concentrations of a weak acid and its conjugate base are not comparable in a solution?
The buffer will have a limited capacity to resist pH changes, especially if a strong acid or base is added that exceeds the concentration of the limiting component.
What is the effect of [weak acid] = [conjugate base]?
The buffer is at its maximum buffer capacity.