Which activity from the following is exhibited by a $Lewis$ base according to its definition?

Complete the following Acid-Base reactions and identify each reactant as an Acid or a Base:
$(i)$ $CH_3NH_2 + H_2O$
$(ii)$ $CO_2 + H_2O$
$(iii)$ $H_2PO_4^- + CO_3^{2-}$
$(iv)$ $NH_2NH_2 + H_2O$
$(v)$ $C_6H_6 + NO_2^+$
$(vi)$ $C_6H_6 + NH_2^-$

What is meant by the conjugate acid-base pair? Find the conjugate acid/base for the following species: $HNO_2, CN^{-}, HClO_4, F^{-}, OH^{-}, CO_3^{2-}$ and $S^{2-}$

Which of the following is a Lewis acid?

$HF + HClO_4 \rightleftharpoons H_2F^{+} + ClO_4^-$ 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.

Which of the following is an oxyacid?