Oxidation and reduction

The Wasps and the Bees-A Dynamic Analogy. Hugh MacBride. The Polvtechnic chestei~oad. Sunderland S R 1 3SD. UNITED KINGDOM. A variety of interesting ...
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aid andogie/ Oxidation and Reduction

RON

Middle Georgia College Cochran. Georgia 31014

The Wasps and the Bees-A Dynamic Analogy

Marten

Hugh M a c B r i d e

Aletta

The Polvtechnic chestei~oad Sunderland S R 1 3SD UNITED KINGDOM

J. ten Hoor Jacobsscholengemeenschap

Nieuweweg 4 9603 EM Hoogezand Nederland

White1 used the followine analow ".to exdain that in a redox reaction the oxidator is reduced, and the reductor is simultaneouslv oxidized: as one Dours a liauid from a full bottle (the filler) into an empty glass &heemptier), the filler gets e m p t ~ e d while the emptier gets filled. I t seems that this analogy may he pushed a little further. Let a full filler represent an oxidator and an empty emptier a reductor. The liquid streaming from the filler into the emptier then symbolizes the conventional electric current (which occurs when the redox reaction proceeds in a cell). Let the volume of the filler be a measure of the oxidator strength (standard electrode potential). Then the fact that a LARGE, full filler can fill a SMALL, empty emptier, but not the other wav round. means that a strone oxidator can oxidize the reduced form of a weaker oxidator, whereas a weak oxidator cannot oxidize the reduced form of a stronger oxidator. Thus, using a set of glasses decreasing in size, a series of displacement reactions may he imitated. And, if the liquid used is an alcoholic refreshment, the demonstrator might empty the last full glass into himself, thereby gaining a higher state of (int)oxid&on.

' White, A. D., J. CHEM.EDUC.,58,645 (1981). This feature oresents a collection of descriotive aoolications and an.. aIo(j.e5oes p e g .o na 0 slieenis .n6erswnq some ol ineatll c.1, con. cnpt+freqrenl, enco..n!erea in cnemslr, Conlr %.I ons rn?! * # IproOLCC .I groilt~rapprcc al m ,.nlnr c n cuge LIpcl i cii rc g ou3 economic, historical, and scientific aspects of life are encouraged.

132

Journal

of Chemical Education

edited by: DELORENZO

A variety of interesting and amusing analogies have been presented for the process of chromatographic separation, but most do not convev the nature of the dvnamic eauilihrium depends. I have used the following analogy fog several years with apparent success. Imagine that a swarm of bees has become mixed (by some entomological freak) with a swarm of wasps, and suppose that the mixed swarm drifts in a gentle breeze to the up-wind end of a long bed of flowers. The hees gather pollen from the flowers, flying from one flower to the next, so that on average they spend, say, half their time resting on the flowers and half in the air. Wasps, having no interest m flowers, remain in the air all the time so that they move at the speed of the wind. When the wasps reach the end of the bed the bees will be only half-way down, since, being airborne for only half the time, thev move with onlv half the widspeed. The swarms will not be dispersed very much by the process since all insects of each type move at the same speed, except for those individuals who spend more or less than the average time on flowers or in flying with or against the wind. The analogy can be extended to ilhatrate the differing response factors of most chromatographic detectors to different substances: A scantily clad sunbather sheltering in the lee of the flowers detects the eluted insects when they emerge and sting her. The sting of the bee is more painful than that of the wasp, so that the intensitv of her resuonse does not dlrectlv indicate the re'etlve numbers of the two species.