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Polyprotic Acids and Beyond—An Algebraic Approach

Umwelt- und Ingenieurtechnik GmbH Dresden (UIT), Zum Windkanal 21, 01109 Dresden, Germany
Academic Editor: Edwin Charles Constable
Chemistry 2021, 3(2), 454-508; https://doi.org/10.3390/chemistry3020034
Received: 3 March 2021 / Revised: 18 March 2021 / Accepted: 19 March 2021 / Published: 7 April 2021
(This article belongs to the Section Theoretical Chemistry)
For an N-protic acid–base system, the set of nonlinear equations (i.e., mass action and balance laws) provides a simple analytical solution/formula for any integer N ≥ 1. The approach is applicable for the general case of zwitterionic acids HNA+Z (e.g., amino acids, NTA, and EDTA), which includes (i) the “ordinary acids” as a special case (Z = 0) and (ii) surface complexation. Examples are presented for N = 1 to 6. The high-N perspective allows the classification of equivalence points (including isoionic and isoelectric points). Principally, there are two main approaches to N-protic acids: one from hydrochemistry and one “outside inorganic hydrochemistry”. They differ in many ways: the choice of the reference state (either HNA or A−N), the reaction type (dissociation or association), the type/nature of the acidity constants, and the structure of the formulas. Once the (nonlinear) conversion between the two approaches is established, we obtain a systematics of acidity constants (macroscopic, microscopic, cumulative, and Simms). Finally, from the viewpoint of statistical mechanics (canonical isothermal–isobaric ensemble), buffer capacities, buffer intensities, and higher pH derivatives are actually fluctuations in the form of variance, skewness, and kurtosis. View Full-Text
Keywords: polyprotic acids; acid–base equilibria; titration; buffer capacity; equivalence points; zwitterions; alkalinity; amino acids; surface complexation polyprotic acids; acid–base equilibria; titration; buffer capacity; equivalence points; zwitterions; alkalinity; amino acids; surface complexation
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MDPI and ACS Style

Kalka, H. Polyprotic Acids and Beyond—An Algebraic Approach. Chemistry 2021, 3, 454-508. https://doi.org/10.3390/chemistry3020034

AMA Style

Kalka H. Polyprotic Acids and Beyond—An Algebraic Approach. Chemistry. 2021; 3(2):454-508. https://doi.org/10.3390/chemistry3020034

Chicago/Turabian Style

Kalka, Harald. 2021. "Polyprotic Acids and Beyond—An Algebraic Approach" Chemistry 3, no. 2: 454-508. https://doi.org/10.3390/chemistry3020034

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