A2: Buffers Flashcards
1
Q
What does a buffer solution contain?
A
Weak acid (HA) and its conjugate base (A-)
2
Q
What is the role of a buffer solution?
A
Aims to minimise pH changes when a small amount of acid or alkali is added
3
Q
How can a buffer be prepared?
A
Mixing a weak acid and its salt, or partial neutralisation of a weak acid (excess of the acid)
4
Q
How does a buffer control pH?
A
1) contains reservoirs of HA and A-
2) equilibrium HA <–> H+ +A- is present
3) acid added, H+ + A- -> HA, shifting the position of equilibrium to the left
4) alkali added, OH- + H+ -> H2O, shifting p.o equilibrium to the right
