Samenstelling van de oplossing tijdens monoprotische zuur-/basetitraties

Recall that the titration of acetic acid with sodium hydroxide produces sodium acetate and water, resulting in a buffer.

The relative concentration of the different species in the buffer solution during various points of the titration is indicated by the alpha values.

While the curved line represents titration of acetic acid and sodium hydroxide, the straight lines labeled alpha-knot and alpha-one denote the relative equilibrium concentration of acetic acid and acetate ions, respectively.

Initially, the alpha-knot value of 0.987, suggests that 98.7% of the acetic acid is undissociated, with the remaining 1.3% constituting acetate ions.

At the cross-over point or the half-equivalence point, pH equals pK_a. Accordingly, the solution has an equal concentration of acetic acid and acetate ions.

As the titration proceeds, the concentration of the acetic acid, alpha-knot, decreases to nearly zero at the equivalence point. Alternatively, the concentration of the acetate ions, alpha-one, increases and approaches unity.