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Use of Salt in Buffer Solution

Posted: Mon Nov 30, 2015 10:22 pm
by Shani Chung 2C
If you're trying to create a buffer solution with a weak acid, for instance CH3COOH, you add a salt containing it's conjugate base, CH3COO-, in order to make [CH3COOH]= [CH3COO-]. However, doesn't CH3COO- prefer it's molecular form? So won't it react with water to form CH3COOH?

Re: Use of Salt in Buffer Solution

Posted: Tue Dec 01, 2015 1:15 am
by Ronald Yang 2F
I think that preference is stronger when NaOH is added to CH3COOH. For a buffer solution, both CH3COOH and CH3COO- are actually pretty weak, so rarely would either react with water. That's why they are good for making buffer solutions. They concern only themselves and not water (ex. strong acid added, CH3COO- takes H+ from acid and makes CH3COOH, and vice versa). Here's more information on buffers: http://chemcollective.org/activities/tutorials/buffers/buffers3