单项选择题

A.CN-[KθaHCN)=6.2×10-10]
B.S2-[Kθa1(H2S)=1.3×10-7,Kθa2(H2S)=7.1×10-15]
C.CH3COO-[Kθa(CH3COOH)=1.8×10-5]
D.F-[Kθa(HF)=3.5×10-4]