A Buffer Solution with a PH of 4

Multiple Choice

A buffer solution with a pH of 4.40 is prepared with 0.78 M Na C₂H₃O₂ and ________ M HC₂H₃O₂. The K_a of HC₂H₃O₂ is 1.8 × 10^-5.

A) 1.7
B) 3.5
C) 4.1 × 10⁴
D) 0.35
E) 0.86