In $NH_3$ and $PH_3$,the common property is

Arrange $NH_4^+$,$H_2O$,$H_3O^+$,$HF$,and $OH^-$ in increasing order of their acidic strength.

When hydrogen chloride is dissolved in acetic acid,the following equilibrium is established: $HCl + CH_3COOH \rightleftharpoons Cl^- + CH_3COOH_2^+$. Identify the conjugate acid-base pairs.

Identify the conjugate acid and conjugate base for the $HCO_3{ }^{-}$ ion,respectively.

What will be the conjugate acid-base pair in the reaction $HCl_{(aq)} + H_2O_{(aq)} \rightleftharpoons H_3O^{+}_{(aq)} + Cl^{-}_{(aq)}$?

Which one is not an acid salt?