The following compounds are available as 0.10 M aqueous solutions: pyridine (pKb = 8.82), triethylamine (pKb = 3.25), HClO4, phenol (pKa = 9.96), HClO (pKa = 7.54), NH3 (pKb = 4.74) and NaOH. Identify two solutions that could be used to prepare a buffer with a pH of approximately 5.
◦ pyridine and HClO4
◦ triethylamine and HClO4
◦ phenol and NaOH
◦ HClO and NaOH
◦ HClO and NH3