Ch109_LectureNotes

**Predicted pH for salt solutions (1 M)**
Salt		pH
KCN	strong base, weak acid salt K⁺ + H₂O NR CN^- + H₂O HCN + OH^-	>7
KC₂H₃O₂	strong base, weak acid salt K⁺ + H₂O NR C₂H₃O₂^- + H₂O HC₂H₃O₂ + OH^-	>7
NH₄Cl	weak base, strong acid salt NH₄⁺ + H₂O NH₃ + H₃O⁺ Cl^- + H₂O NR	<7
NH₄ NO₃	weak base, strong acid salt NH₄⁺ + H₂O NH₃ + H₃O⁺ NO₃^- + H₂O NR	<7
NH₄CN	NH₃ stronger than HCN NH₄⁺ + H₂O NH₃ + H₃O⁺ CN^- + H₂O HCN + OH^-	>7
NH₄C₂H₃O₂	pK_{b NH₃} = pK_{a HC₂H₃O₂} NH₄⁺ + H₂O NH₃ + H₃O⁺ C₂H₃O₂^- + H₂O HC₂H₃O₂ + OH^-	7

Stephen E. Bialkowski's relative fractions of phosphoric acid species with pH

Stephen E. Bialkowski's Phosphoric Acid Titration Curve

H₃PO₄ H⁺ + H₂PO₄^- 2 H⁺ + HPO₄^2- 3 H⁺ + PO₄^3-

Rxn K_a pK_a

H₃PO₄ H⁺ + H₂PO₄^- K_{a 1} = 7.5 x 10^-3 2.2

H₂PO₄^- H⁺ + HPO₄^2- K_{a 2} = 6.2 x 10^-8 7.2

HPO₄^2- H⁺ + PO₄^3- K_{a 3} = 4.8 x 10^-13 12.7

Elements Video PT Video

© R A Paselk

Last modified 10 May 2013

Rxn	K_a	pK_a
H₃PO₄ H⁺ + H₂PO₄^-	K_{a 1} = 7.5 x 10^-3	2.2
H₂PO₄^- H⁺ + HPO₄^2-	K_{a 2} = 6.2 x 10^-8	7.2
HPO₄^2- H⁺ + PO₄^3-	K_{a 3} = 4.8 x 10^-13	12.7