Azide ion behaves like chloride in the silver nitrate test

Steps:

• Dissolve NaN3 in water to get N3- ions.
• Acidify to ensure complete ionization; add AgNO3 to form white AgN3 precipitate (similar to AgCl).
• Add aqueous ammonia, which complexes with Ag+ as [Ag(NH3)2]+, dissolving the precipitate.
• Predict outcome based on N3- similarity to Cl-, where AgCl dissolves in dilute NH3.

Why A is correct:

• AgN3, like AgCl, is soluble in aqueous ammonia due to formation of the diamminesilver(I) complex, [Ag(NH3)2]+(aq).

Why the others are wrong:

• B: No AgN compound forms; precipitate is AgN3, and solution isn't specified as colourless.
• C: Precipitate dissolves, doesn't remain, unlike AgBr.
• D: Same as C; precipitate dissolves in ammonia.

Final answer: A