Buffer Solutions Flashcards
What is an acid-base buffer?
A solution that resists change in pH when a small amount of a strong acid or base is added
What are the components of a buffer solution?
A conjugate acid-base pair
Adding an ion to an equilibrium mixture containing that ion and the equilibrium shifting away from forming it.
Common ion effect – how pH buffers work
In a pH buffer, what component consumes small amounts of added OH from a strong base?
The acidic component of the buffer
In a pH buffer, what component consumes small amounts of added hydronium from a strong acid?
The basic component of the buffer
If you add a small amount of a strong acid to a buffered solution, what happens to the pH?
It becomes very slightly more acidic
If you add a small amount of a strong base to a buffered solution, what happens to the pH?
It becomes very slightly more basic
Do buffer components consume all added H3O and OH, or only some?
Buffer components consume nearly all H3O and OH
What is the Henderson-Hasselbalch equation?
pH = pKa + log([A-]/[HA])
What is buffer capacity?
The strength of a buffer, its ability to maintain pH
Do buffer solutions with higher concentrations of their components have higher or lower capacity?
Higher
What is buffer range?
The pH range over which a buffer is effective
What is the range of a buffer relative to the pKa of the acid component?
pH = pKa plus or minus 1 pH unit
How do you choose the acid component for a buffer solution knowing the desired pH?
The pKa of the acid should be near the desired pH
What does the Henderson-Hasselbalch equation do?
Calculates the pH of a buffer system
