Academic Year 2019/2020 - 2° Year
Teaching Staff: Alberto TORRISI
Credit Value: 6
Scientific field: CHIM/01 - Analytical chemistry
Taught classes: 21 hours
Exercise: 36 hours
Term / Semester:

Learning Objectives

At the end of the course, the student should be able to calculate the chemical composition of an aqueous solution in presence of Broensted acid-base equilibria and/or complexation equilibria and/or precipitation-solubility equilibria.

Course Structure

Lectures and numerical exercices.

Detailed Course Content

Introduction - Chemical equilibrium – Equilibrium constant – Factors affecting the equilibrium constant; composition, solvent, temperature. Systematic treatment of equilibrium. Mass, charge and proton balances.

Acid-base equilibria – Broensted and Lewis theories – Conjugate acid-base pair – Strength of acids and bases – Water ionic product and pH – Acidity and neutrality of an aqueous solution - Strong acids or strong bases aqueous solution; rigorous and approximate treatments; criteria and validity limits – Weak monoprotic acids or weak monoacid bases aqueous solution; dissociation degree; rigorous and approximate treatments; criteria and limits of validity – Aqueous solution containing one conjugate polyprotic acid or one polyacid base; rigorous and approximate treatments - Composition vs. pH expression; distribution plot - Aqueous solution containing a conjugate acid-base pair; rigorous and approximate treatments; buffers; buffer capability – Aqueous solution containing a conjugate polyprotic acid - polyacid base pair –– Ampholytes - Aqueous solution containing mixture of acids and bases (strong-strong, weak-strong, strong-weak, weak-weak); rigorous and approximate treatments.

Complex formation equilibria – monodentate and polydentate ligands, chelate effect, partial formation , global formation and conditional formation constants, pH influence.

Precipitation equilibria - Solubility and solubility product - Selective precipitation, gravimetry - Influence of Broensted and Lewis acid-base interaction on the solubility of salts containing monovalent and polyvalent cations and anions.

Activity - Relationship between activity and concentration – Thermodynamic and stoichiometric constants – Ionic strength – Short outline of Debye Hückel theory and its practical application on ionic equilibrium.

Volumetric methods; generality, titration graphs, end-point indicators.

  • Acid-base titrations; strong acid, strong base, weak acid, weak base, polyprotic acid, polyacid base - Titration criteria - Acid-base indicators - Titration error.
  • EDTA complexation titrations; pH choice, auxiliary complexing agents, indicators, titration error – Liebig titration.
  • Precipitation titration: generality - Silver nitrate as precipitation agent - Visualization of titration end-point by Möhr, Volhardt and Fajans methods - Titration error.

Textbook Information

- Daniel Harris - Quantitative Chemical Analysis, 9th edition, W.H. Freeman and Company, New York, 2016

- Douglas A. Skoog, Donald M. West, F. James Holler, Stanley H. Crouch - Foundamentals of Analytical Chemistry, 9th edition, Brooks/Cole, Cengage Learning, 2014