Wonder why this was not part of Chemistry class, ever!

Belousov–Zhabotinsky Reaction
Like most kids growing up in India, I was encouraged to take up science after my secondary school and expected to make a career in medicine or engineering somewhere. While the debate will always continue whether such encouragement is good for the child or not, as a student of science, there was a lot of information that was being bombarded at me, some of which I liked and some of which I just could not get my head around. Unfortunately, Chemistry features in the list of subjects, I didn't understand completely.

There are so many things that happen in the Chemistry textbook and to make matters worse, it is further divided into Chemistry I and Chemistry II (the organic and the inorganic parts). There was only one way to get past the barrier and that was understand what you could and regurgitate it in the exams to the best of your ability. I think I managed it quite well for my board exams but then came the larger hurdle of biochemistry and knowing the intricate details of various biochemical cycles such as Krebs cycle (citric acid cycle), Urea Cycle or breakdown of Glucose in the body etc. The dry nature of their contents further pushed me away from Chemistry, so much so that we hardly cover any Chemistry in this at Coffee Table Science. But that is some thing we are looking to change in the coming posts and hope this will be a good start. 

While researching a little on the Chemistry frontier for the blog, I came across an amazing phenomenon called Oscillating reactions. Right from the first reaction that was taught in school till date, chemistry was always a means to an end, One component reacted with another or probably even more to form a final product and that was where Chemistry ended. 

We studied chemistry to know how the end product is made. 


Even as we grew up and the famous Krebs cycle was introduced, it was introduced as how A is converted to B and then to C, till it finally returns as A, but not as how beautifully does the cell use its resources to produce energy. In my honest most opinion, it would not have hurt the makers of chemistry textbooks to start with oscillating reactions to get the student interested at least before boring them to death with Friedel-Crafts Alkylation

A common example of an oscillating chemical reaction is the Belousov-Zhabotinsky reaction, where reaction constituents. In the 1950's Russian biochemist Boris Belousov observed that in a mixture of chemicals that consisted of potassium bromate and cerium sulfate among other things, the reaction liquid did not reach an end point but kept oscillating between colours yellow and  colourless. While Belousov tried to publish his findings, the then popular journals dismissed his findings since the results did not agree with the common notion that all chemical reactions reach an end point and make a stable product


It was only a decade later that Anatol Zhabotinsky, who was working at the University of Moscow came across Belousov's findings and investigated them further. Unfortunately, he, too, wasn't able to publish his findings at that time and it was only another decade later in 1972 when the mechanism of oscillating reactions was finally published. The reason for colour changes of the solution is the oscillating oxidation state of Cerium which is yellow in a higher oxidation state and colourless in a lower oxidation state.

Since then, there are many reaction mixes that have been described that follow the principle of Belousov-Zhabotinsky reaction and one such is shown below using ferroin, which I found on Stephen Morris' YouTube Channel



I am quite sure that had some one showed me this video 10 years ago, my attitude towards chemistry would have been very very different. Would yours have been?

Do let us me know using the comments section below!


Share this:

0 comments:

Post a Comment

Please let us know your thoughts in the comments section below.