試題詳解

18. A 0.15 M solution of a weak acid is 3.0% dissociated. The K_a of the acid is calculated to be .
(A) 3.5 × 10^-4
(B)4.2 × 10^-3
(C) 1.4 × 10^-4
(D) 2.4 × 10^-2
(E)3.6 × 10^-3