Among $CO_3^{2-}$,$OH^{-}$,$NH_3$ and $HCO_3^{-}$,the species that acts as a Bronsted acid as well as a Bronsted base,is

The species among the following,which can act as an acid and a base is

In the following reactions,$ZnO$ is respectively acting as a/an:

Urea is preferred to ammonium sulphate as a nitrogenous fertilizer because

Which among the following is the strongest acid?

When one equivalent of an acid is mixed with an excess of a strong base,which of the following acids will show the maximum rise in the temperature of the solution?