Acid-base Answer.3.
a. NH3 gains an H+ to become NH4+, making it the base. HNO2 loses the H+ to become NO2, making it the acid.
b. CH3COOH loses the proton on the end, making it the acid. OH gains an H+ to become water, making it the base.
c. H2O gains H+ to become H3O+, so it is the base. HSO4 loses its H+ to become SO42, so it is the acid.
d. In this case H2O is the acid, losing H+ to be OH. (It depends on the reaction!) HS is the base, gaining H+ to be H2S.
e. HS is the acid. It loses H+ to become S2. CO32 is the base; it gains H+.