Flashcards in 8.8 Buffer Solutions Deck (8)
What is a buffer solution?
One which resists changes in pH when small amounts of acid or alkali are added.
What does a buffer solution contain?
Two components and must always contain something to react with any acid added and something to react with any base added.
What is an acidic buffer solution?
A solution of a weak acid (HA) and the salt/conjugate base of that weak acid.
What is the equilibrium that exists in the acidic buffer solution?
HA (aq) H+ (aq) + A- (aq)
What happens if acid is added to the buffer solution?
A- (aq) + H+(aq) -----> HA (aq)
What happens if alkali is added to the buffer solution?
HA(aq) + OH-(aq) -----> A-(aq) + H2O (l)
Why do small changes in the concentration of HA and A- not change the position of the original equilibrium?
Because large amounts of HA and A- are present and hence the pH remain approximately constant.