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Concept Question Q7B 2009 Final

Posted: Wed Dec 02, 2015 8:39 pm
by JohnArthurReyes_1B
How is autoprotolysis related to the concept that [H3O+]+[OH-]=14? The problem asks for the concentration of acetic acid when the autoprotolysis of water needs to be taken to account. All we're given is KA=10^-7 M

Re: Concept Question Q7B 2009 Final

Posted: Wed Dec 02, 2015 11:40 pm
by Chem_Mod
Water undergoes autoprotolysis so in sol'n, it will generate [H3O+] and [OH-] ions. When you add in acetic acid, it can react with the OH- ions generated by water.

Re: Concept Question Q7B 2009 Final

Posted: Sun Dec 06, 2015 2:22 pm
by JuliaPark2H
This also confused me as well, but remember how autoprotolysis just refers to water's reaction within itself as an acid or a base-- losing or gaining a proton. Kw of neutral water is 10^-14, where [H+]=[OH-]=10^-7. If either [H+] or [OH-] concentration is off, I conceptualize that it triggers autoprotolysis. And since formic acid is an acid, any concentration that makes [H+] less than 10^-7 will bring in autoprotolysis. I hope my thought process is correct.