In the reaction where $HNO_3$ acts as a base,which of the following acts as the strongest acid?

Which of the following species can act as both a Bronsted acid and a Bronsted base?

Which of the following species can act as a Bronsted-Lowry acid as well as a Bronsted-Lowry base?

Identify the amphoteric species among the following:
$(I) \, H_2O$
$(II) \, NH_2^-$
$(III) \, H_2PO_4^-$
$(IV) \, HCO_3^-$

Which salt can furnish $H^{+}$ ion in its aqueous solution?

The values of dissociation constants $(K_a)$ of some acids (at $25\,^{\circ}C$) are as follows. Indicate which is the strongest acid in water:
$(A)$ $1.4 \times 10^{-2}$
$(B)$ $1.6 \times 10^{-4}$
$(C)$ $4.4 \times 10^{-10}$
$(D)$ $4.3 \times 10^{-7}$