Chemistry - Ionic Equilibrium Question with Solution | TestHub

$\mathrm{NaF}$: salt of a weak acid, solution basic, $\left[{\mathrm{H}}_3{\mathrm{O}}^{+}\right]$ below $10^{-7}\mathrm{M}$.

${\mathrm{KNO}}_3$: neutral, $10^{-7}\mathrm{M}$.

$\mathrm{HF}$: weak, $\left[{\mathrm{H}}^{+}\right]\approx 2\times 10^{-3}\mathrm{M}$.

${\mathrm{HNO}}_3$: strong, 0.01 M.

${\mathrm{H}}_2{\mathrm{SO}}_4$: first step is complete (0.01 M) and the second step adds about $4.5\times 10^{-3}\mathrm{M}$, so $\left[{\mathrm{H}}^{+}\right]\approx 0.0145\mathrm{M}$.

Order: $\mathrm{NaF}<{\mathrm{KNO}}_3<\mathrm{HF}<{\mathrm{HNO}}_3<{\mathrm{H}}_2{\mathrm{SO}}_4$.

Answer: (C).