Is ethylenediamine a weak base? When titrated with HCl, what would its titration curve look like? Is it diprotic?

Answer 1

Yes, with the first H+ added stronger than ammonia. It is weak and diprotic as it can form two ammonium ions. The curve would look like two esses with two equivalence points, but going downhill as you add a strong acid. Check sodium carbonate and HCl for visual.