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Topic: Buffer question PLS HELP  (Read 2724 times)

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Offline slutsavenue

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Buffer question PLS HELP
« on: September 30, 2013, 03:58:29 AM »
A sodium acetate-acetic acid buffer solution was prepared by adding 0.020 M HCl solution to 500 ml
of 0.020 M Ch3COONa and then diluting the mixed solution to 1.0L. Calculate the original volume of the
HCl solution needed to prepare a buffer solution of pH 5.00.

The given answer is 180ml.

How do I derive the original volume of HCL solution needed to prepare the buffer solution? I used the henderson hesselberg equation in attempt to solve this answer but can't seem to get the given answer.

Offline Borek

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Offline magician4

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Re: Buffer question PLS HELP
« Reply #2 on: September 30, 2013, 11:34:57 AM »
the allegedly correct answer "180 mL " is WRONG

taking 4.75 as pKa for acetic acid , the correct answer would have to be 281,17 mL ~ 280 mL


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Offline Borek

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Re: Buffer question PLS HELP
« Reply #3 on: September 30, 2013, 11:59:12 AM »
the allegedly correct answer "180 mL " is WRONG

taking 4.75 as pKa for acetic acid , the correct answer would have to be 281,17 mL ~ 280 mL

180 mL is perfectly correct, please stop confusing people.
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