titreringskurvan

titreringskurvan, or titration curve, is a graphical representation of the pH of a solution as a function of the volume of titrant added during a titration. The curve is generated by recording the pH of the titration mixture after each addition of the titrant and plotting these data points. The shape of the curve reflects the acid‑base properties of the analyte and the titrant, and it is an essential tool for determining the equivalence point and for selecting an appropriate indicator.

In a strong acid–strong base titration, the curve displays a steep rise near the equivalence point, with pH values progressing from below 1 to well above 13 as the added base neutralises the acid. For weak acid–strong base systems, the curve rises more gradually, reaching a pH around 8–9 at equivalence. Conversely, a strong acid–weak base titration shows a sharp decline to a pH around 5–6. The buffer region, located near the half‑equivalence point, is characterised by a relatively flat portion of the curve; this region is crucial for accurate determination of the pKa of weak acids or weak bases.

The equivalence point is identified where the slope of the curve is maximal, and the volume of titrant at this point is used to calculate the concentration of the analyte. The use of indicators is guided by the pH at or near the equivalence point; an indicator that changes colour at a pH slightly beyond the anticipated equivalence point ensures a visible transition. Precise measurement of pH and careful control of titrant addition improve the reliability of the curve and the resulting quantitative analysis.