diwa_sb {titrationCurves}

Titration Curve for Diprotic Weak Acid

Description

This function calculates and plots the titration curve for a diprotic weak acid analyte using a monoprotic strong base as the titrant. The calculation uses a single master equation that finds the volume of titrant needed to achieve a fixed pH, as outlined in R. de Levie's Principles of Quantitative Chemical Analysis (McGraw-Hill, 1997).

Usage

diwa_sb(conc.acid = 0.1, conc.base = 0.1, pka1 = 5, pka2 = 9,
  pkw = 14, vol.acid = 50, plot = TRUE, eqpt = FALSE, overlay = FALSE,
  ...)

Arguments

conc.acid

Molar concentration of the diprotic weak acid analyte; defaults to 0.10 M.

conc.base

Molar concentration of the strong base titrant; defaults to 0.10 M.

pka1

The pKa1 value for the diprotic weak acid analyte; defaults to a pKa1 of 5.

pka2

The pKa2 value for the diprotic weak acid analyte; defaults to a pKa2 of 9.

pkw

The pKw (or pKs) value for the solvent; defaults to water as a solvent with a pKw of 14.

vol.acid

Initial volume, in mL, of the solution that contains the weak acid analyte; defaults to 50.00 mL.

plot

Logical; if TRUE, plots the titration curve.

eqpt

Logical; if TRUE, draws a vertical line at the titration curve's equivalence point.

overlay

Logical; if TRUE, adds the current titration curve to the existing titration curve.

...

Additional arguments to pass to plot() function.

Value

A two-column data frame that contains the volume of titrant in the first column and the solution's pH in the second column. Also produces a plot of the titration curve with options to display the equivalence point and to overlay titration curves.

Author(s)

David T. Harvey, DePauw University. [e-mail]

Examples

### Simple titration curve with equivalence points
ex5 = diwa_sb(eqpt = TRUE)
head(ex5)

### Overlay titration curves using different pKa1 and pKa2 values
diwa_sb(pka1 = 5, pka2 = 9, eqpt = TRUE)
diwa_sb(pka1 = 6, pka2 = 10, overlay = TRUE)
diwa_sb(pka1 = 4, pka2 = 8,  overlay = TRUE)