Question: is nh3 is acid or base?
Answer: Both NH3 and H2O are amphoteric (they have H atoms that can be donated as H+ ions and thus act as acids and lone-pair electrons that can accept an H+ and thus act as bases). Thus, either NH3 or H2O can act as an acid or a base. When NH3 is mixed in H2O there is a competition for the proton.