What is buffer solution I'm using it in my chemistry coursework for GCSE and I need to know pleez xxxxx

They are, very basically, solutions which resist small changes of pH, they generally work by, upon the addition of acid or alkali, the equilibrium in he mixture is disturbed, and a reaction occurs to return it to the same pH.

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Buffer solution - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Buffer_solution)