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Sukham_5277
#1 Posted : Wednesday, August 19, 2020 5:08:57 PM
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Hello,
I was wondering if you could explain why c is the correct answer and why the other answers are incorrect.

The pH of a 1 L phosphate buffer solution was measured as 7.6, but the experimental procedure calls for a pH 7.2 buffer. Which method will adjust the solution to the proper pH? (Note: The pKa values for phosphoric acid are 2.2, 7.2, and 12.3.)

A.Add enough 1 M Na2HPO3 to increase the phosphate anion concentration ten-fold.
B.Add 1 M NaOH to neutralize a portion of the hydronium ions found in the solution.
C.Alter the ratio of monosodium/disodium phosphate added to favor the monosodium species.
D.Add 100 mL distilled, deionized water to dilute the basicity of the buffer.

Thanks!
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INSTR_Katerina_102
#2 Posted : Friday, August 21, 2020 12:59:10 AM
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Hi Sukham,

I have attached a worked example here:https://alumniubcca-my.sharepoint.com/:i:/g/personal/katerina_schwab_alumni_ubc_ca/Ea8RDU0jXd1Eo7n8b5Ov35kBm5tlvj3tfxIodvcnbuhbDg?e=i7EZKe

Please let me know if you would like a more detailed explanation.

Thanks,

Katt
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