Heating iron sulfide produces sulfur oxide,which reacts with water to form an acid. What is the basicity of this acid?

Select the amphoteric substance from the following:

Which one of the following ionic species has the greatest proton affinity to form a stable compound?

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 conjugate base.

Observe the following species: $AlCl_3, NH_3, H^{+}, Co^{3+}, OH^{-}, Mg^{2+}, BF_3, Cl^{-}$. How many Lewis acids are present in the above list?

State the Lewis acid-base principle.