The compound $HCl$ behaves as $...$ in the reaction,$HCl + HF \to H_2Cl^{+} + F^{-}$

The ionization constants of $HF$,$HCOOH$,and $HCN$ at $298 \ K$ are $6.8 \times 10^{-4}$,$1.8 \times 10^{-4}$,and $4.8 \times 10^{-9}$ respectively. Calculate the ionization constants of their corresponding conjugate bases.

The order of decreasing basic strength of halides is:

When $K_2O$ is added to water,the solution becomes basic in nature because it contains a significant concentration of

The species: $H_{2}O$,$HCO_{3}^{-}$,$HSO_{4}^{-}$,and $NH_{3}$ can act both as Bronsted acids and bases. For each case,give the corresponding conjugate acid and base.

Which one of the following arrangements represents the correct order of the proton affinity of the given species?