What Molar Ratio of CH₃COOH to CH₃COONa Should Be Used

Multiple Choice

What molar ratio of CH₃COOH to CH₃COONa should be used in order to prepare an acetic acid / sodium acetate buffer solution with a pH of 4.00 ± 0.02? [K_a(CH₃COOH) = 1.8 × 10^-5]

A) 0.18
B) 0.84
C) 1.2
D) 5.6
E) 0.10