Conjugate acid for Bronsted base.
Conjugate acid of a Bronsted-Lowry base is the species formed after an acid accepts a proton. So, the conjugate acid will have one proton extra.
NH–2+H+→NH3
NH3+H+→NH+4
HCOO−+H+→HCOOH
The corresponding conjugate acids are: NH3, NH+4 and HCOOH respectively.