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Diffusion

There is also the classic experiment with concentrated ammonia and hydrochloric acid placed on plugs of cotton wool at opposite ends of a glass tube. After a while a white ring forms in the tube due to the interaction of the two chemicals. The differing masses of the molecules means that they diffuse through the air in the tube at different rates and the white ring formed in a tube when they meet will not be in the centre.


Safety - take every precaution when handling the bottles of concentrated ammonia and hydrochloric acid
 
 
 
© Keith Gibbs/John Bourne 2008