Chemical waves in the iodide-nitric acid system

Istvan P. Nagy, Andrea Keresztessy, John A. Pojman, György Bazsa, Z. Noszticzius

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Chemical waves can be observed during the oxidation of iodide by 3-4.5 M nitric acid. The rate of the wave propagation and the wave shape under convection-free and convective conditions were studied using tubes with different diameters and at varying orientations to the gravitational vector. The activation energy of the reaction-diffusion front was determined. For the homogeneous reaction, the isothermal density change (Δρc) was measured and found to be negative. Because the reaction is exothermic, the Pojman and Epstein analysis of convective stability predicted only simple convection could occur. However, double-diffusive convection and fingering were observed. With special convection cells fed through permeable membranes we proved that double-diffusive convection could occur by having two solutal species (iodide and triiodide-starch complex) with significantly different diffusion coefficients and not only from competing thermal and solutal density changes. A mechanism for the angular dependence of the gravitational anisotropy in front velocities is proposed in terms of the Boycott effect.

Original languageEnglish
Pages (from-to)6030-6037
Number of pages8
JournalJournal of Physical Chemistry
Volume98
Issue number23
Publication statusPublished - 1994

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Nitric Acid
nitric acid
Iodides
Nitric acid
iodides
convection
convection cells
exothermic reactions
starches
free convection
Exothermic reactions
wave propagation
diffusion coefficient
Starch
Natural convection
Wave propagation
activation energy
tubes
membranes
oxidation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Nagy, I. P., Keresztessy, A., Pojman, J. A., Bazsa, G., & Noszticzius, Z. (1994). Chemical waves in the iodide-nitric acid system. Journal of Physical Chemistry, 98(23), 6030-6037.

Chemical waves in the iodide-nitric acid system. / Nagy, Istvan P.; Keresztessy, Andrea; Pojman, John A.; Bazsa, György; Noszticzius, Z.

In: Journal of Physical Chemistry, Vol. 98, No. 23, 1994, p. 6030-6037.

Research output: Contribution to journalArticle

Nagy, IP, Keresztessy, A, Pojman, JA, Bazsa, G & Noszticzius, Z 1994, 'Chemical waves in the iodide-nitric acid system', Journal of Physical Chemistry, vol. 98, no. 23, pp. 6030-6037.
Nagy IP, Keresztessy A, Pojman JA, Bazsa G, Noszticzius Z. Chemical waves in the iodide-nitric acid system. Journal of Physical Chemistry. 1994;98(23):6030-6037.
Nagy, Istvan P. ; Keresztessy, Andrea ; Pojman, John A. ; Bazsa, György ; Noszticzius, Z. / Chemical waves in the iodide-nitric acid system. In: Journal of Physical Chemistry. 1994 ; Vol. 98, No. 23. pp. 6030-6037.
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