what is difference between ammonia and ammonium
Ammonia is a compound with the formula NH3, it is a weak base. Ammonium is a polyatomic ion with the formula NH4+.The ammonium ion is formed when ammonia reacts with an acid and is itself mildly acidic. because it is positively charged is is not found on its own but accompanied by a negative ion such as in ammonium nitrate, NH4NO3.mmonia is a compound with the formula NH3, it is a weak base. Ammonium is a polyatomic ion with the formula NH4+.