You mix equal volumes of 0.05 M NaH₂PO₄ and 0.05 M Na₂HPO₄ (pK's for phosphoric acid are 2.15,6.82 and 12.38).Which of the following best describes the resulting solution? A)pH 2.15 and poorly buffered B)pH 2.15 and well buffered C)pH 6.82 and well buffered D)pH 12.38 and well buffered E)pH 6.82 and poorly buffered

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Quizplus · Accepted Answer

When equal volumes of NaHS and NaH2PO4 are mixed, the resulting solution is a buffer system with a pH of approximately the average of the pKa values, which in this case is 6.82. Moreover, since the pKa of H2PO4- is closer to the pH of the buffer (6.82), this buffer will be more efficient at resisting changes in pH when small amounts of acid or base are added, thus making it a well-buffered solution.

You Mix Equal Volumes of 0