Consider the following acids and bases:

HCO2H	Ka = 1.8 × 10-4
HOBr	Ka = 2.0 × 10-9
(C2H5)2NH	Kb = 1.3 × 10-3
HONH2	Kb = 1.1 × 10-8

Choose substances from the following list that would be the best choice to prepare a pH = 6.0 buffer solution.

(Select all that apply.)

HONH₂

KHCO₂

HCO₂H

(C₂H₅)₂NH

(C₂H₅)₂NH₂Cl

HOBr

NaOBr

HONH₃NO₃