Acid-base titrations

Download

• • Titration.vi - LabVIEW Virtual Instrument (requires LabVIEW version 2010 or higher); zip file with all subVIs; main VI is called Titration VI.vi

  • Titration.exe - Stand-alone executable (download folder and run setup.exe to install)

  • JavaScript version - runs directly in web browser

Description

Titration displays theoretical curves for the tiration of a mono-, di-, or tri-protic acid with a strong base, or the titration of a mono-, di-, or tri-protic base with a strong acid. All pKa and pKb values are selectable, as are the concentrations of all solutions and the volume of analyte titrated. Titration curves may be displayed alone, or with first- or second-derivative plots as well.

Front panel

Guiding questions

• • 1. Simulate the titration of 50 mL of 0.100 M acid with 0.100 strong base and notice how the curve changes with pKa of the acid.  On paper, make a sketch of a these curves on a single plot for pKa values of -1, 3, 5, 7, 9, and 11.  What do you always notice about the pH after 25 mL of base has been added?

    2. Simulate the titration of 50 mL of 0.100 M base with 0.100 strong acid and notice how the curve changes with pKb of the base.  On paper, make a sketch of a these curves on a single plot for pKb values of -1, 3, 5, 7, 9, and 11.  What do you always notice about the pH after 25 mL of acid has been added?

    3. When titrating a monoprotic acid or base, how does the concentration of the acid or base being titrated affect the ability to see a clear equivalence point on the curve?

    4. What factors determine how many equivalence points are clearly visible in the titration of a polyprotic acid with a strong base?

    5. What factors determine how many equivalence points are clearly visible in the titration of a polyprotic base with a strong acid?

    6. What is the benefit of showing first- or second-derivative plots of the titration?