68. Arrange following 0.10 M solutions from lowest to highest pH: NaF, NaC2H3O2, C5H5NHCl, KOH, HCN. (Ka for HCN is 6.2 × 10-10; Ka for HF is 7.2 × 10-4; Ka for HC2H3O2 is 1.8 × 10-5; Kb for C5H5N is 1.7 × 10-9) (A) HCN, C5H5NHCl, NaF, NaC2H3O2, KOH (B) C5H5NHCl, HCN, NaF, NaC2H3O2, KOH (C) NaF, NaC2H3O2, HCN, C5H5NHCl, KOH (D) KOH, NaC2H3O2, NaF, HCN, C5H5NHCl (E) None of these