$H^{+}$ is a

Which of the following is a Lewis base?

For the species $HSO_4^{-}$ and $NH_3$,their conjugate acids respectively are

The dissociation of $H_3PO_4$ occurs in how many stages?

Write the conjugate base of the following: $HF, CH_{3}NH_{3}^{+}, H_{3}PO_{4}, HPO_{4}^{2-}$

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.