Fundamentals of analytical chemistry

The course aims to provide the basis of solution equilibria and quantitative chemical analysis. The student will learn to deal with problems related to real systems at equilibrium in aqueous solution using the knowledge acquired as well as adequate language and exposition skills (Dublin indicator 1). In particular, he/she should be able to determine the chemical composition of an aqueous solution in the presence of acid-base and/or precipitation and/or complexation equilibria (Dublin 2 indicator). He/she will have to know the main applications of solution equilibria to volumetric analysis.

Class lectures and exercises on ionic equilibria in solution.

Should teaching be carried out in mixed mode or remotely, it may be necessary to make changes with respect to the previous statements, in line with the programme planned and outlined in the syllabus.

To guarantee equal opportunities and in compliance with current laws, interested students can ask for a personal interview in order to plan any compensatory and/or dispensatory measures, based on their specific needs and on teaching objectives of the discipline. It is also possible to ask the departmental contacts of CInAP (Center for Active and Participatory Integration - Services for Disabilities and/or DSAs).

Basic principles of Mathematics and General Chemistry.

1. Basic concepts on chemical equilibria: Chemical equilibrium. Thermodynamic and stoichiometric equilibrium constant. Factors affecting the equilibrium constant: composition, solvent, temperature. Systematic treatment of ionic equilibria. Mass, charge and proton balance equations. Activity. Correlation among activity, concentration, activity coefficients and equilibrium expression. Ionic strength. Correlation between ionic strength and activity coefficient: Debye Hückel theory.

2.1 Acid-base equilibria: Acid-base theories. Conjugate acid-base pair. Ionic product of water. Definition of pH, acidity and neutrality of an aqueous solution. Strength of acids and bases. Strong acids and bases aqueous solution. Rigorous and approximate treatment of equilibria: criteria and validity limits. Weak monoprotic acids and monoacid bases. Degree of dissociation. Rigorous and approximate treatment of equilibria: criteria and validity limits. Solutions containing a conjugated acid-base pair. Buffer solutions. Rigorous and approximate treatment of equilibria: criteria and limits of validity. Buffer capacity. Solutions of polyprotic acids and polyacid bases. Rigorous and approximate treatment. Composition as a function of pH. Distribution diagrams. Ampholytes. Solutions containing conjugated pairs of polyprotic acids and polyacid bases. Rigorous and approximate treatment. Mixtures of non-conjugated acids and bases.

2.2  Acid-base titrations: Volumetric methods: general information. Concepts of titration, equivalence point and end point. Titration error. Acid-base indicators. Titration curves: strong acid-strong base, strong base-strong acid, monoprotic weak acid-strong base, monoacid weak base-strong acid, polyprotic acid-strong base, polyacid base-strong acid. Rigorous and approximate treatment.

3. Complexation equilibria: Complexes. Monodentate and polydentate ligands. Chelate effect. Thermodynamic formation constant. Treatment of complexation equilibria. Effect of pH on complexation equilibria. EDTA, acid-base and complexing properties. Conditional formation constant. Minimum operating pH.

3.1 Complexometric titrations: Titrations with EDTA. Titration curve and rigorous/approximate treatment. Effect of the auxiliary complexing agent. Indicators. Titration error.

4. Solubility equilibria: Ionic product, solubility and solubility product. Influence of ionic strength, temperature, solvent. Effect of the common ion, pH and complex formation on the solubility of a poorly soluble salt. Simultaneous and selective precipitation.

4.1 Precipitation titrations: Titration curve: rigorous and approximate treatment. Titration error. Titration of halides with the Mohr, Fajans and Volhard methods.

1. H. Freiser, Q. Fernando, “Gli Equilibri Ionici nella Chimica Analitica", Piccin, Padova;
2. D. C. Harris, “Fondamenti di Chimica Analitica“, terza ed., Zanichelli, Bologna – Zanichelli;
3. F. J. Holler, S. R. Crouch, “Fondamenti di Chimica Analitica”, terza ed., Edises, Napoli;
4. Detailed slides of the lessons made available on Studium.

Written and oral test.

The written test will contain exercises similar to those discussed and solved during classes. The oral test, accessible only after successfully passing the written test, will assess the general understanding of all topics presented during the course.

The tests might be carried out also remotely/on-line if required by special conditions/events.

Voting follows the following scheme:

Below 18:

Knowledge and understanding of the topic: Important deficiencies. Significant inaccuracies.
Analysis and synthesis skills: Irrelevant. Frequent generalizations. Inability to synthesize.
Use of references: Completely inappropriate.

18-20
Knowledge and understanding of the topic: At threshold level. Obvious imperfections.
Analysis and synthesis skills: Just sufficient skills.
Use of references: As appropriate.

21-23
Knowledge and understanding of the topic: Routine knowledge.
Analysis and synthesis skills: Able to correctly analyze and summarize. Argues logically and coherently.
Using references: Uses standard references.

24-26
Knowledge and understanding of the topic: Good knowledge.
Analysis and synthesis skills: Has good analysis and synthesis skills. The topics are expressed coherently.
Using references: Uses standard references.

27-29
Knowledge and understanding of the topic: More than good knowledge.
Analysis and synthesis skills: Has considerable analysis and synthesis skills.
Use of references: The topics are deeply explored.

30-30L
Knowledge and understanding of the topic: Excellent knowledge.
Analysis and synthesis skills: Has considerable analysis and synthesis skills.
Using references: Important insights.

- Dependence of the equilibrium constant on temperature or ionic strength.
- Calculation of the pH of a solution containing a weak mono/diprotic acid at various dilutions.
- Buffer capacity and criteria for preparing a buffer solution.
- Titration curve of a weak mono/bifunctional acid/base with a strong component.
- Optimal conditions for the titration of a cation with EDTA.
- Qualitative and quantitative factors that influence the solubility of a poorly soluble salt.