Acetic acid acetate buffer

Hägg diagram of acetic acid (pKa = 4.7).
black = acetic acid, purple = acetate

The acetic acid / acetate buffer is a buffer system consisting of acetic acid and sodium acetate . The pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation .

If oxonium or hydroxide ions are added in not too large amounts of substance, the pH value only decreases or increases very slightly. This is the general way chemical buffer solutions work.

Acetic acid / acetate buffer:

{\ displaystyle \ mathrm {HOAc + H_ {2} O \ \ rightleftharpoons \ AcO ^ {-} + H_ {3} O ^ {+}}}

Addition of oxonium ions:

{\ displaystyle \ mathrm {AcO ^ {-} + H_ {3} O ^ {+} \ \ longrightarrow \ HOAc + H_ {2} O}}

Addition of hydroxide ions:

{\ displaystyle \ mathrm {HOAc + OH ^ {-} \ \ longrightarrow \ AcO ^ {-} + H_ {2} O}}

The weak acid releases protons to neutralize the hydroxide ions. Their corresponding base acts as a proton acceptor .

Individual evidence

^ Hans Peter Latscha, Helmut Alfons Klein, Martin Mutz: Allgemeine Chemie . 10th, completely revised edition. Springer, Heidelberg, Dordrecht, London, New York 2011, ISBN 978-3-642-17523-7 , pp. 239 , doi : 10.1007 / 978-3-642-17523-7 .

[1] Hans Peter Latscha, Helmut Alfons Klein, Martin Mutz: Allgemeine Chemie . 10th, completely revised edition. Springer, Heidelberg, Dordrecht, London, New York 2011, ISBN 978-3-642-17523-7 , pp. 239 , doi : 10.1007 / 978-3-642-17523-7 .