Choose specific acid-base conjugate pairs to make a buffer with a pH = 8.64
Use the table below for your choices:
Acids: Acetic acid, Hypobromous acid, Hypochlorous acid, Hydrogen sulfide, Oxalic acid, Phosphoric acid
Formula: CH3COOH, HBrO, HClO, H2S, HOOCCOOH, H3PO4
Ka: 1.8 x 10^-5, 2.8 x 10^-9, 2.9 x 10^-8, 8.9 x 10^-8, 5.6 x 10^-2, 7.5 x 10^-3