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Topic: Buffer solution  (Read 3355 times)

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Offline suomi

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Buffer solution
« on: September 10, 2011, 05:30:33 PM »
Can anybody help me with this problem? Thanks!

Given 0.1 M solutions of acetic acid and acetate, describe the preparation of 1 L of 0.1 M acetate buffer at a pH of 5.4.

Offline Arkcon

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Re: Buffer solution
« Reply #1 on: September 10, 2011, 07:56:59 PM »
Are you aware of any formulas that you can use to relate concentration to pH for a particular chemical?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline suomi

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Re: Buffer solution
« Reply #2 on: September 10, 2011, 11:40:49 PM »
First I thought, I could use the Handelson-Hasselbalch equation, which is

pH= pKa + log (A-/HAc).

The pKa value of an acetate is 4.76, and the pH should be 5.4.

Since pH= -log[H+], I did 10-5.4 = 3.981*10-6.

I plugged all those three values in the HH equation, but then I didn't know how I should relate 0.1M of the buffer.

Other equation I thought about was C= n/V, but I am just stuck in the problem and can't see the big picture...


Offline Borek

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Re: Buffer solution
« Reply #3 on: September 11, 2011, 04:18:56 AM »
So far so good.

0.1M buffer means sum of concentrations of acetic acid and acetate is 0.1M.
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