Consider the reaction below. nh4+ + h2o mc013-1.jpg nh3 + h3o+ which is an acid-conjugate base pair? nh4+ and nh3 nh4+ and h3o+ h2o and nh3 h2o and h3o+

NH4+ and NH3 are an acid-conjugate base pair, since NH4+ is an acid, while NH3 is its conjugate base (since it is without the H+).
H2O and H3O+ can also be considered an acid-conjugate base pair, since H3O+ is an acid, while H2O would be its conjugate base. (But if only 1 answer is to be selected, it should be the NH4+ and NH3)
NH4+ and H3O+ are both acids, and both H2O and NH3 can be considered bases.

What does that mean you dum bum