Unit: Equilibrium in Aqueous Solution Module: Buffers [page 1 of 1]
• A basic buffer is a buffer that has been designed in such a way that it can resist
large changes in pH and keep a solution in the basic realm.
• If acid is added to a buffer solution, the weak base will react with the acid
forming a weak acid and water until all of the weak base is consumed.
• If base is added to a buffer solution, the weak acid will react with the base forming
a weak base and water until all of the weak acid is consumed.
In order to create a basic buffer it is necessary to
use a base which reacts more with water that its
conjugate acid. i.e. b > Ka.
Basic buffer problems are K broblems. To get the
Kbof the conjugate base apply the equality
K = K • K
w a b
Using K bt is possible to compute the pH of the
buffer system where pH = 14 – pOH.
0.10 mol HCl added to 0.30 mol NH in3enough