6. 請將以下各為 0.10 M 的溶液由 pH 值低到高排列 :NaF,NaC
2H
3O
2,C
5H
5NHCl, KOH,HCN (HCN: K
a = 6.2 × 10
–10; HF: K
a = 7.2 × 10
–4 ; HC
2H
3O
2: K
a = 1.8 × 10
–5 ; C
5H
5N: Kb =1.7 × 10
–9 )
(A) C5H5NHCl, HCN, NaF, NaC2H3O2, KOH
(B) NaF, NaC2H3O2, HCN, C5H5NHCl, KOH
(C) KOH, NaC2H3O2, NaF, HCN, C5H5NHCl
(D) HCN, C5H5NHCl, NaF, NaC2H3O2, KOH