Which of the following cannot act both as Bronsted acid and as Bronsted base?

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.

The neutralization of a strong acid by a strong base liberates an amount of energy per mole of $H^{+}$ that:

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

Ammonia is a Lewis base because it is

$HF + HClO_4 \rightleftharpoons H_2F^{+} + ClO_4^-$ and $H_2O + H_2PO_4^- \rightleftharpoons H_3O^{+} + HPO_4^{2-}$ Select the group of acidic species present on the right side of the equilibrium.