(Solution) - The 0 025 0 m KH2PO4 0 025 0 m Na2HPO4 buffer 6 -(2025 Original AI-Free Solution)

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The 0.025 0 m KH2PO4/0.025 0 m Na2HPO4 buffer (6) in Table 14-3 has a pH of 6.865 at 25°C.
(a) Show that the ionic strength of the buffer is ? = 0.100 m.
(b) From the pH and K2 for phosphoric acid, find the quotient of activity coefficients, , at  = 0.100 m.
(c) You have the urgent need to prepare a pH 7.000 buffer to be used as a calibration standard.45 You can use the activity coefficient ratio from part (b) to accurately prepare such a buffer if the ionic strength is kept at 0.100 m. What molalities of KH2PO4 and Na2HPO4 should be mixed to obtain a pH of 7.000 and ? = 0.100 m?