Question

where do you find the excess analyte and excess titrant on a potentiometric plot?

Answer 1

For a potentiometric plot(potentiometric titration curve) we use several methods,

1)a direct plot of pH or cell potential Vs Volume of titrant,The midpoint in the steeply rising portion of the curve taken as the end point or equivalence point.

2)First derivative curve by calculating the change in pH or potential per unit volume of titrant(E/V or pH/V) it produces a curve with a maximum that corresponds to end point or equivalence point.

Before the equivalence point ,the analyte is in excess

after the equivalence point the titrant is in excess