In a tail wagging the dog reversal, researchers have found that simple chemical reactions can mix a solution. Usually, chemicals are stirred to enhance a reaction, but a new study finds that the reverse is also true: Simple chemical reactions can trigger fluid flows, reports a paper in the January 29 Physical Review Letters.
sciencenewsThe research has implications for many chemical reactions, including those inside stars or when carbon dioxide stored deep in the earth encounters water, says study coauthor Anne De Wit of the Université Libre de Bruxelles in Belgium.
De Wit and her colleagues wondered what would happen to fluid flows if the reacting liquids were left alone and not stirred. The researchers watched a very simple reaction — the neutralization that occurs between hydrochloric acid and sodium hydroxide, a common chemical base — in the absence of stirring.
The researchers carefully injected the denser sodium hydroxide into a container and then added the hydrochloric acid. The sodium hydroxide stayed on the bottom and the hydrochloric acid sat on top. Where the two reactive chemicals met, the reaction’s products — table salt and water — began to form. As the salty solution formed, it crept upward and hit the lower-density acid, creating tendrils that started to mix the solution. But the same didn’t happen below the reaction line. This difference in how the reaction product interacted with each of its chemical parents drove the mixing the team observed.
Read More http://www.wired.com/wiredscience/2010/01/self-stirring-liquids/#ixzz0e5Dq3OQa
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