Weak acid

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A weak acid is an acid chemical which does not dissociate (split into ions) completely when in a water solution. This means it does not give all its hydrogen ions into the water. Weak acids typically have a pH between 3 and 6.

Acetic acid (CH3COOH) and oxalic acid (H2C2O4) are examples of weak acids. If an acid is represented by HA, then there is a balance between molecules which are split (ionised), and molecules which are not:

\mathrm{ HA_{(aq)} \, \leftrightarrow \, H^+\,_{(aq)} +\, A^-\,_{(aq)} }