Acidic Salts: Salts resulting from the reactions of a strong acid with a weak base (the salt will have a cation from a weak base) will undergo hydrolysis and make the solution acidic. Ex) Salt produced by the reaction of a Strong Acid with a Weak Base HCl + NH3 NH4Cl ⇌ Will react with water to yield a conjugate base and a hydronium ion (makes solution acidic) NH4Cl + H2O NH3 + H3O+ + Cl- ⇌ Salts resulting from the reactions of a weak acid with a strong base (the salt will have an anion Basic Salts: from a weak acid) Ex) Salt produced by the reaction of a Weak Acid with a Strong Base HF + NaOH NaF ⇌ + H2O Will react with water to yield a conjugate acid and a hydroxide ion (makes solution basic) NaF + H2O HF + OH- + Na+ ⇌ Common Ions and Relative pH Ions of Neutral Salts Cations Basic Ions Acidic Ions Na+ K+ Rb+ Cs+ F- C2H3O2- NO2- HCO3- NH4+ Al3+ Pb2+ Sn2+ Mg2+ Ca2+ Sr2+ Ba2+ CN- CO32- S2- SO42- Transition metal ions Anions HPO42- PO43- HSO4- H2PO4- Cl- Br- I-, ClO4- BrO4- ClO3- NO3- Calculating pH of a salt solution Ex) Calculate the pH of a 0.500 M solution of KCN. Ka for HCN is 5.8 x 10-10. Write the equation for the dissolving process, and examine each ion formed to determine whether the salt is an acidic, basic, or neutral salt. KCN(s) → K+(aq) + CN-(aq) K+ is a neutral ion and CN- is a basic ion. KCN is a basic salt. Write the equation for the reaction of the ion with water and the related equilibrium expression.
Acidic Salts: Salts resulting from the reactions of a strong acid with a weak base (the salt will have a cation from a weak base) will undergo hydrolysis and make the solution acidic. Ex) Salt produced by the reaction of a Strong Acid with a Weak Base HCl + NH3 ⇌ NH4Cl Will react with water to yield a conjugate base and a hydronium ion (makes solution acidic) NH4Cl + H2O ⇌ NH3 + H3O+ + Cl- Basic Salts: Salts resulting from the reactions of a weak acid with a strong base (the salt will have an anion from a weak acid) Ex) Salt produced by the reaction of a Weak Acid with a Strong Base HF + NaOH ⇌ NaF + H2O Will react with water to yield a conjugate acid and a hydroxide ion (makes solution basic) NaF + H2O ⇌ HF + OH- + Na+ Common Ions and Relative pH Ions of Neutral Salts Cations Na+ K+ Rb+ Cs+ Mg2+ Ca2+ Sr2+ Ba2+ Anions Cl- Br- I-, ClO4- BrO4- ClO3- NO3- Acidic Ions NH4+ Al3+ Pb2+ Sn2+ Transition metal ions HSO4- H2PO4- Basic Ions F- C2H3O2- NO2- HCO3- CN- CO32- S2- SO42- HPO42- PO43- Calculating pH of a salt solution Ex) Calculate the pH of a 0.500 M solution of KCN. Ka for HCN is 5.8 x 10-10. Write the equation for the dissolving process, and examine each ion formed to determine whether the salt is an acidic, basic, or neutral salt. KCN(s) → K+(aq) + CN-(aq) K+ is a neutral ion and CN- is a basic ion. KCN is a basic salt. Write the equation for the reaction of the ion with water and the related equilibrium expression.
Acid_base_lecture_2015-2016.docx