By definition, a(n) acid is any species that can donate a proton. Ammonia has a proton bonded to nitrogen, so ammonia can be an base (although a very weak one). A(n) base is a proton acceptor, that is, it must have a pair of electrons to share with a proton. In theory, any atom with an unshared electron pair can be a pair so ammonia is a proton; instead, it acts as a base and pulls a proton from water to a small extent. base The nitrogen in ammonia has an unshared electron In water, ammonia is too weak an -to give up its