The chemical chameleon is a redox reaction, well known from classroom demonstrations, that exploits the dramatic color changes associated with the various oxidation states of manganese.[1][2]
Chemical chameleon reaction
Glauber reported the first description of the production of potassium permanganate when he noted that manganese dioxide (as the mineral pyrolusite) could be reacted at high temperatures with alkali to obtain a material that dissolved in water to give a green solution which slowly shifted to a violet-red.[3] This process, similar to that still used in the production of potassium permanganate,[4] oxidized manganese dioxide to potassium manganate which, acidified by carbon dioxide absorbed from the air, oxidized further to purple potassium permanganate.
The chemical chameleon reaction shows the process in reverse, by reducing violet potassium permanganate first to green potassium manganate and eventually to brown manganese dioxide:[1][2][5]
The reaction proceeds in alkaline conditions under the influence of a reducing agent. Sodium hydroxide, potassium hydroxide, and ammonium hydroxide can be used to alkalize the permanganate solution, while a variety of reducing agents can be used, sugars being common.[1][5][8]
A similar demonstration involves soaking paper in alkalized permanganate solution, which produces the same color changes as the paper is oxidized and the permanganate reduced.[9]
Referencesedit
^ abc. Archived from the original on 2015-07-06. Retrieved 2014-03-20.
^ abOxidation states and the Chemical Chameleon Catholic High School Science and Maths Society
^Weeks, M. E. and Leicester, H. M.; Discovery of the Elements, Journal of Chemical Education 1968
^Reidies, Arno H. (2002) "Manganese Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_123
^. Archived from the original on 2015-03-16. Retrieved 2014-03-20.
^Schmidt, Max (1968). "VII. Nebengruppe". Anorganische Chemie II (in German). Wissenschaftsverlag. pp. 100–109.
^(PDF). Thames & Kosmos. p. 53. Archived from the original (PDF) on 2013-04-07. Retrieved 2014-03-20.
^Thompson, Robert Bruce (17 February 2012). "Lab 10.2: Oxidation States of Manganese". Illustrated Guide to Home Chemistry Experiments. ISBN9781449331429.
April 12, 2024
chemical, chameleon, chemical, chameleon, redox, reaction, well, known, from, classroom, demonstrations, that, exploits, dramatic, color, changes, associated, with, various, oxidation, states, manganese, source, source, source, source, reactionglauber, reporte. The chemical chameleon is a redox reaction well known from classroom demonstrations that exploits the dramatic color changes associated with the various oxidation states of manganese 1 2 source source source source Chemical chameleon reactionGlauber reported the first description of the production of potassium permanganate when he noted that manganese dioxide as the mineral pyrolusite could be reacted at high temperatures with alkali to obtain a material that dissolved in water to give a green solution which slowly shifted to a violet red 3 This process similar to that still used in the production of potassium permanganate 4 oxidized manganese dioxide to potassium manganate which acidified by carbon dioxide absorbed from the air oxidized further to purple potassium permanganate The chemical chameleon reaction shows the process in reverse by reducing violet potassium permanganate first to green potassium manganate and eventually to brown manganese dioxide 1 2 5 KMnO4 violet K2MnO4 green MnO2 brown yellow suspension Blue potassium hypomanganate may also form as an intermediate 6 Oxidation states of manganese 7 7 KMnO4 violet 6 K2 MnO4 green 5 K3 MnO4 blue 4 MnO2 yellow The reaction proceeds in alkaline conditions under the influence of a reducing agent Sodium hydroxide potassium hydroxide and ammonium hydroxide can be used to alkalize the permanganate solution while a variety of reducing agents can be used sugars being common 1 5 8 A similar demonstration involves soaking paper in alkalized permanganate solution which produces the same color changes as the paper is oxidized and the permanganate reduced 9 References edit a b c Science Brothers The Chemical Chameleon Archived from the original on 2015 07 06 Retrieved 2014 03 20 a b Oxidation states and the Chemical Chameleon Catholic High School Science and Maths Society Weeks M E and Leicester H M Discovery of the Elements Journal of Chemical Education 1968 Reidies Arno H 2002 Manganese Compounds in Ullmann s Encyclopedia of Industrial Chemistry Wiley VCH Weinheim doi 10 1002 14356007 a16 123 a b The Chemical Chameleon Ontario Institute for Studies in Education Archived from the original docx on 20 March 2014 Retrieved 20 March 2014 Faculty of Science Perth University Chemistry experiment KMnO4 NaOH sugar Archived from the original on 2015 03 16 Retrieved 2014 03 20 Schmidt Max 1968 VII Nebengruppe Anorganische Chemie II in German Wissenschaftsverlag pp 100 109 Chem C3000 Experiment Manual PDF Thames amp Kosmos p 53 Archived from the original PDF on 2013 04 07 Retrieved 2014 03 20 Thompson Robert Bruce 17 February 2012 Lab 10 2 Oxidation States of Manganese Illustrated Guide to Home Chemistry Experiments ISBN 9781449331429 Retrieved from https en wikipedia org w index php title Chemical chameleon amp oldid 1094983511, wikipedia, wiki, book, books, library,
