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Topic: Very "basic" acid base question  (Read 4290 times)

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PJB

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Very "basic" acid base question
« on: May 27, 2005, 11:23:29 AM »
Boy, am I getting myself confused!  My text tells me that “adding a base to any solution raises the pH of the solution”, and that makes sense,  but what do I get when I add NaOH to H20?   Don’t I get H3O, which would be lowering the pH?  I realize that this is extremely fundamental, and it is very sad for a poor soul like me to get so lost so easily.  

Another thought, when adding a strong base and weak acid, the solution is basic because the acid forms it’s conjugate base, not because of the addition of the strong base (strong bases neutralize)  Am I  correct in my understanding of that?

If anyone can tell me where my thought processes are going wrong, please do!  I think that I am probably getting stuff twisted around somehow, but I need some help to straighten it all out.
Pam
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Offline Borek

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Re:Very "basic" acid base question
« Reply #1 on: May 27, 2005, 11:32:07 AM »
Don’t I get H3O, which would be lowering the pH?

No. You will get H3O+ dissolving acid. Adding base you get just OH-.

Quote
Another thought, when adding a strong base and weak acid, the solution is basic because the acid forms it’s conjugate base, not because of the addition of the strong base (strong bases neutralize)

If you add more strong base then there was acid in the solution, situation is obvious - pH is high due to the presence of strong base.

When the amount of strong base is lower than amount of weak acid only part of the acid is neutralized. Neutralized acid is a conjugate base. This conjugate base reacts with water (hydrolize) inccreasing pH.
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