NH4+ is acid as it give a proton tobecome NH3, a base NO2- is a base as it can take a protonto become HNO2 , an acid HCO3- is a base as it can take proton tobecome an acid, H2CO3 HS- is a base as it can take a proton to become anacid, H2S H3O+ is an acid F- is a base as it can take a proton to become HF,an acid HS- is a base as it can take a proton to become anacid, H2S H3O+ is an acid F- is a base as it can take a proton to become HF,an acid Solution NH4+ is acid as it give a proton tobecome NH3, a base NO2- is a base as it can take a protonto become HNO2 , an acid HCO3- is a base as it can take proton tobecome an acid, H2CO3 HS- is a base as it can take a proton to become anacid, H2S H3O+ is an acid F- is a base as it can take a proton to become HF,an acid HS- is a base as it can take a proton to become anacid, H2S H3O+ is an acid F- is a base as it can take a proton to become HF,an acid.