14. Fluoroantimonic acid is formed by reacting hydrogen fluoride with antimony pentafluoride. The resulting mixture is complex but can be simplified as shown in the equilibrium below. Choose the INCORRECT statement regarding this reaction. $$ \mathrm{SbF_5} + 2 \mathrm{HF} \rightleftharpoons \mathrm{SbF_6^-} + \mathrm{H_2F^+} $$ (A) HF acts as a Lewis base (B) HF acts as a Brønsted acid (C) HF acts as a Lewis acid (D) HF acts as a Brønsted base (E) $\mathrm{SbF_5}$ acts as a Lewis acid

22. Cerium(IV) ion is a strong oxidizing agent that accepts one electron to produce cerium(III) ion. A solution containing an unknown concentration of $Sn^{2+}$ ions was titrated with a solution containing $Ce^{4+}$ ions, which oxidize the $Sn^{2+}$ ions to $Sn^{4+}$ ions. In one titration $1.00\ \mathrm{L}$ of the unknown solution required $46.45\ \mathrm{mL}$ of a $0.1050\ \mathrm{M}\ Ce^{4+}$ solution to reach the stoichiometric point. $$ a\ Ce^{4+}(aq) + b\ Sn^{2+}(aq) \longrightarrow c\ Ce^{3+}(aq) + d\ Sn^{4+}(aq) $$ What is the closest concentration of $Sn^{2+}$ ions in the unknown solution? (A) $2.4 \times 10^{-3}$ (B) $2.4 \times 10^{-2}$ (C) $2.7 \times 10^{-3}$ (D) $2.7 \times 10^{-2}$ (E) $3.0 \times 10^{-3}$

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