Answer
a. $NH_{4}$+ is its conjugate acid.
b. $HClO_{4}$ is its conjugate acid.
c. $H_{2}SO_{4}$ is its conjugate acid.
d. $HCO_{3}$- is its conjugate acid.
Work Step by Step
a. $NH_{4}$+ is its conjugate acid because it can donate a hydrogen proton as it has an extra H+ ion.
b. $HClO_{4}$ is its conjugate acid because it can donate a hydrogen proton as it has an extra H+ ion.
c. $H_{2}SO_{4}$ is its conjugate acid because it can donate a hydrogen proton as it has an extra H+ ion.
d. $HCO_{3}$- is its conjugate acid because it can donate a hydrogen proton as it has an extra H+ ion.