Dissolution of AgCl by Complexation with NH3​
Authors: Housam Binous

​We study the dissolution of silver chloride (AgCl) in ammoniacal medium through complex formation. The code calculates the distribution of silver species
+
Ag
,
+
Ag(NH3)
, and
+
Ag(NH3)
2
​ as a function of ammonia concentration.​Using equilibrium constants and the solubility product of AgCl, the code determines the variation of solubility S and plots:​• the distribution diagram of silver complexes, • and the evolution of lo
g
10
[⁡S] versus pNH3​. ​The results show that increasing ammonia concentration favors the formation of soluble silver ammine complexes, especially
+
Ag(NH3)
2
, which significantly increases the solubility of AgCl.​​References: ​[1] https://ressources.univ-lemans.fr/AccesLibre/UM/Pedago/chimie/01/05-Chimie-en-solution/deug/pdf/Chimie_solution.pdf
Additsional theoretical backgound about complexation enhanced dissolution of AgCl
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ClearAll["Global`*"]​​​​​​(*Constants*)​​pKD1=3.2;​​pKD2=3.83;​​pKs=9.75;​​​​KD1=10^-pKD1;​​KD2=10^-pKD2;​​Ks=10^-pKs;​​​​​​(*NH3concentration*)​​NH3[pNH3_]:=10^-pNH3;​​​​​​(*Distributiondenominator*)​​Den[pNH3_]:=1+NH3[pNH3]/KD1+NH3[pNH3]^2/(KD1KD2);​​​​​​(*Fractionaldistributions*)​​alpha0[pNH3_]:=1/Den[pNH3];​​alpha1[pNH3_]:=(NH3[pNH3]/KD1)/Den[pNH3];​​alpha2[pNH3_]:=(NH3[pNH3]^2/(KD1KD2))/Den[pNH3];​​​​​​(*Solubility*)​​S[pNH3_]:=Sqrt[Ks*(1+NH3[pNH3]/KD1+NH3[pNH3]^2/(KD1KD2))];​​​​logS[pNH3_]:=Log10[S[pNH3]];
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(*Distributiondiagram*)​​distPlot=Plot[{alpha0[p],alpha1[p],alpha2[p]},{p,0,7},PlotStyle->{{Darker@Red,Thick},{Darker@Blue,Thick},{Darker@Green,Thick}},Frame->True,AspectRatio->1,FrameLabel->{Style["
pNH
3
",15],Style["α",15]},PlotRange->{{0,7},{-0.05,1.05}},ImageSize->350,GridLines->Automatic,Epilog->{Text[Style["
α
0
",16,Darker@Red],{5.8,0.95}],Text[Style["
α
1
",16,Darker@Blue],{5.0,0.075}],Text[Style["
α
2
",16,Darker@Green],{0.5,0.95}]},PlotLabel->Style["Distribution of Silver Species",14]]
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