In the reversible reaction in water solution

NH3 + H2O <---> NH4+ + OH− ,
what acts as a Bronsted-Lowry acid and what acts as a Bronsted-Lowry base?
1. H2O; NH4+
2. H2O; OH−
3. OH−; NH4+
4. NH3; H2O
5. OH−; H2O

2 answers

Which adds the proton? That's the base.
Which donates the proton? That's the acid.
NH4 is the base & OH- is the acid, correct?