Greetings,
This post covers the meaning and derivation of the Henderson-Hasselbalch equation. The equation is derived directly from the acid-ionization equation for a generic weak acid, HA. It draws a direct relationship between the molarity of a weak acid and the molarity of its congugate base, A-. The Henderson-Hasselbalch equation is utilized in the laboratory to predict buffer solution pH for a particular molar combination of a weak acid and its corresponding anion salt. The equation is especially useful for determining best buffer recipe for a new process or analytical method. The following slide show lays out the derivation.
A buffered equilibrium system is of the form:
HA(aq) <==> H+(aq) + A-(aq)
MA(aq) + H+(aq) <==> M+(aq) + HA(aq) (Assuming the addition of extra acid)
Note that the second equilibrium effectively absorbs additional acid, thereby preventing a lowering of solution pH.
There will be more on buffered systems in my next post.
As always, thank you for reading!
A Publication of http://ExcellenceInLearning.biz
This post covers the meaning and derivation of the Henderson-Hasselbalch equation. The equation is derived directly from the acid-ionization equation for a generic weak acid, HA. It draws a direct relationship between the molarity of a weak acid and the molarity of its congugate base, A-. The Henderson-Hasselbalch equation is utilized in the laboratory to predict buffer solution pH for a particular molar combination of a weak acid and its corresponding anion salt. The equation is especially useful for determining best buffer recipe for a new process or analytical method. The following slide show lays out the derivation.
A buffered equilibrium system is of the form:
HA(aq) <==> H+(aq) + A-(aq)
MA(aq) + H+(aq) <==> M+(aq) + HA(aq) (Assuming the addition of extra acid)
Note that the second equilibrium effectively absorbs additional acid, thereby preventing a lowering of solution pH.
There will be more on buffered systems in my next post.
As always, thank you for reading!
A Publication of http://ExcellenceInLearning.biz