Monovalent Acid Titration (Eric Bakker, University of Geneva)
Author
Eric Bakker
Title
Monovalent Acid Titration (Eric Bakker, University of Geneva)
Description
Classical titration calculation and interactive plots. Plot pH and associated chemical species as a function of strong acid volume as titrant.
Category
Educational Materials
Keywords
Acid-base titration, manipulate, chemical speciation
URL
http://www.notebookarchive.org/2020-05-6xtfrje/
DOI
https://notebookarchive.org/2020-05-6xtfrje
Date Added
2020-05-15
Date Last Modified
2020-05-15
File Size
57.41 kilobytes
Supplements
Rights
CC BY 4.0
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Titration of a weak monovalent acid
Titration of a weak monovalent acid
Quantitative Analysis Course
Prof. Eric Bakker
University of Geneva, Switzerland
Prof. Eric Bakker
University of Geneva, Switzerland
Equations
Equations
Dissociation constant of the acid:
e1=kaha/ha;
Autoprotolysis of water:
e2=ke==hoh;
Charge balance:
e3=cnaoh+hoh+a;
Mass balance:
e4=chaha+a;
Equivalence considerations to arrive at volume of titrant:
e5=cnaoh(Vinit+Vnaoh)ctitrantVnaoh;
e6=cha(Vinit+Vnaoh)==chainitVinit;
Calculate Titration Curve
Calculate Titration Curve
e7=Eliminate[{e1,e2,e3,e4,e5,e6},{ha,a,oh,cha,cnaoh}]
h(Vinit-chainitkaVinit+hkaVinit+ctitranthVnaoh+Vnaoh+ctitrantkaVnaoh+hkaVnaoh)ke(hVinit+kaVinit+hVnaoh+kaVnaoh)
2
h
2
h
Define experimental parameters (options):
opt={Vinit50,ctitrant1010^logCHAinit};
Calculate endpoint :
Vep=Vinit10^logCHAinit/ctitrant/.opt
5
fVnaoh=Vnaoh/.Solve[e7,Vnaoh][[1]]/.{ka10^-pKa,chainit10^logCHAinit,ke10^-14,h10^-pH}/.opt
-++-+
1-3pH
2
2-3pH
5
-13-pH
2
-12-pH
5
-13-pKa
2
-12-pKa
5
1-2pH-pKa
2
2-2pH-pKa
5
1+logCHAinit-pH-pKa
2
2+logCHAinit-pH-pKa
5
-++(+)
1
100000000000000
1+logCHAinit-pH
10
-2pH
10
-pH
10
-pKa
10
ManipulateParametricPlot,pH,{pH,-1,14},AspectRatio1,PlotRange{{0,2Vep},{0,14}},PlotStyle{Thick,Thick},BaseStyle{16,FontFamily"Helvetica"},FrameLabel{" / mL","pH"},FrameTrue,FrameTicks{{Table[u,{u,2,12,2}],None},{Table[u,{u,0,2Vep,IntegerPart[0.5Vep]}],None}},FrameStyle{Thick,Thick},ImageSize500,Epilog{Text["",{Vep,pKa}],Text[ScientificForm[10^logCHAinitM,2],{1.5Vep,pKa}],Line[{{0,pKa},{0.9Vep,pKa}}]},{{pKa,7},-1,12.5,0.1},{{logCHAinit,0},-7,0,0.1},SaveDefinitionsTrue
-++-+
1-3pH
2
2-3pH
5
-13-pH
2
-12-pH
5
-13-pKa
2
-12-pKa
5
1-2pH-pKa
2
2-2pH-pKa
5
1+logCHAinit-pH-pKa
2
2+logCHAinit-pH-pKa
5
-++(+)
1
100000000000000
1+logCHAinit-pH
10
-2pH
10
-pH
10
-pKa
10
V
NaOH
pK
a
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Speciation
Speciation
Speciation of acid HA :
e8=Eliminate[{e1,e2,e3,e4,e5,e6},{Vnaoh,a,oh,cha,cnaoh}][[1]]
chainitkeVinit(chainitctitranth+chainit-ctitranthha-chainithaka-ctitranthaka)Vinit
2
h
Speciation of conjugate base A :
e9=Eliminate[{e1,e2,e3,e4,e5,e6},{Vnaoh,ha,oh,cha,cnaoh}]
chainitkakeVinith(-actitranth-achainitka-actitrantka+chainitctitrantka+chainithka)Vinit
opt={Vinit50,ctitrant1010^logCHAinit};
Vep=Vinit10^logCHAinit/ctitrant/.opt
5
ha/.Solve[e8,ha][[1]]
chainitctitranth+chainit-chainitke
2
h
ctitranth+chainitka+ctitrantka
fha=ha/.Solve[e8,ha][[1]]/.{ka10^-pKa,chainit10^logCHAinit,ke10^-14,h10^-pH}/.opt
-++
-14+logCHAinit
10
logCHAinit-2pH
10
1+2logCHAinit-pH
10
1+logCHAinit-pH
10
logCHAinit-pKa
10
1+logCHAinit-pKa
10
fha/.{pKa7,logCHAinit-5,pH7}
1
210000
a/.Solve[e9,a][[1]]/.{ka10^-pKa,chainit10^logCHAinit,ke10^-14,h10^-pH}/.opt
pH
10
-14+logCHAinit-pKa
10
logCHAinit-2pH-pKa
10
1+2logCHAinit-pH-pKa
10
1+logCHAinit-pH
10
logCHAinit-pKa
10
1+logCHAinit-pKa
10
ManipulateParametricPlot,(-++)++,,++,{pH,-1,14},AspectRatio1,PlotRange{{0,2Vep},{-0.110^logCHAinit,1.110^logCHAinit}},PlotStyle{Thick,Thick},BaseStyle{16,FontFamily"Helvetica"},FrameLabel{" / mL","[SPECIES] / M"},FrameTrue,FrameTicks{{Table[u,{u,0,10^logCHAinit,0.210^logCHAinit}],None},{Table[u,{u,0,2Vep,IntegerPart[0.5Vep]}],None}},FrameStyle{Thick,Thick},ImageSize500,Epilog{Text[" = ",{Vep,0.510^logCHAinit}],Text[NumberForm[pKa,{3,1}],{1.16Vep,0.50510^logCHAinit}]},{{pKa,7},-1,12.5,0.1},{{logCHAinit,0},-7,0,1},SaveDefinitionsTrue
-++-+
1-3pH
2
2-3pH
5
-13-pH
2
-12-pH
5
-13-pKa
2
-12-pKa
5
1-2pH-pKa
2
2-2pH-pKa
5
1+logCHAinit-pH-pKa
2
2+logCHAinit-pH-pKa
5
-++(+)
1
100000000000000
1+logCHAinit-pH
10
-2pH
10
-pH
10
-pKa
10
pH
10
-14+logCHAinit-pKa
10
logCHAinit-2pH-pKa
10
1+2logCHAinit-pH-pKa
10
1+logCHAinit-pH
10
logCHAinit-pKa
10
1+logCHAinit-pKa
10
-++-+
1-3pH
2
2-3pH
5
-13-pH
2
-12-pH
5
-13-pKa
2
-12-pKa
5
1-2pH-pKa
2
2-2pH-pKa
5
1+logCHAinit-pH-pKa
2
2+logCHAinit-pH-pKa
5
-++(+)
1
100000000000000
1+logCHAinit-pH
10
-2pH
10
-pH
10
-pKa
10
-++
-14+logCHAinit
10
logCHAinit-2pH
10
1+2logCHAinit-pH
10
1+logCHAinit-pH
10
logCHAinit-pKa
10
1+logCHAinit-pKa
10
V
NaOH
pK
a
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Cite this as: Eric Bakker, "Monovalent Acid Titration (Eric Bakker, University of Geneva)" from the Notebook Archive (2020), https://notebookarchive.org/2020-05-6xtfrje
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