20 Chromatography is used to separate a mixture into individual components based on the differences in which properties of the components? (A)particle size (B)boiling point (C)ionic conductivity (D)polarity (E)density

2 Which of the following acids and its sodium salt are the best combination for buffering a solution at pH 4.30? (A)chloroacetic acid (Kₐ=1.35×10⁻³) (B)propanoic acid (Kₐ=1.3×10⁻⁵) (C)benzoic acid (Kₐ=6.4×10⁻⁵) (D)hypochlorous acid (Kₐ=3.5×10⁻⁸) (E)none of the above is acceptable