[besjbo]

I'm told equal volumes of NaI and AgNO₃ are mixed. Also, Ag⁺ exists in aqueous solution as [Ag(H₂O)₂]⁺. Initially, a yellow precipitate of silver iodide forms. This is [Ag(H₂O)(I)], in addition to H₂O.

The addition of 5M NH₃ (aq) causes the yellow precipitate to dissolve and a clear, colorless solution to result. This is [Ag(H₂O)₂]⁺.
The subsequent addition of 5M HNO₃ (aq) causes the yellow precipitate identified as silver iodide to reappear in the clear and colorless solution. Now, I am told that "the formula of the initial product from the Lewis acid-base reaction directly involving HNO₃ is NH₄⁺."

Why is that? How exactly does ammonium come about from the given mixtures

Also, from all of these reactions, how exactly can I determine the order (in terms of strength) of the three bases (NO₃^-, NH₃, and H₂O) with Ag⁺?

[XGen]

The addition of 5M NH₃ (aq) causes the yellow precipitate to dissolve and a clear, colorless solution to result. This is [Ag(H₂O)₂]⁺.

How did you come to this conclusion?