White precipitate of AgCl dissolves in aqueous ammonia solution due to formation of :

Solution

Chemistry ma’am · 3 steps

Ammonia pulls Ag⁺ away from chloride into a soluble complex, and silver stays at +1 throughout.

1. Why it dissolves. AgCl dissolves only very slightly, giving a tiny amount of Ag⁺ and Cl⁻. NH₃ binds that Ag⁺ into a stable, water-soluble complex ion. This removes Ag⁺ from solution, so more solid keeps dissolving until all of it is gone.

   AgCl(s) + 2NH₃(aq) → [Ag(NH₃)₂]⁺(aq) + Cl-(aq)

2. Check silver. No redox happens here, so silver stays Ag⁺, oxidation state +1. With a d¹⁰ configuration, Ag⁺ takes two NH₃ ligands and forms a linear complex with coordination number 2. Testing each option for the oxidation state of Ag rules out three of them.

   Option	Complex	Oxidation state of Ag	Possible?
   (a)	[Ag(NH₃)₄]Cl₂	x + 0 = +2, so +2	No
   (b)	[AgCl₂(NH₃)₂]	x - 2 = 0, so +2	No
   (c)	[Ag(NH₃)₂]Cl	x + 0 = +1, so +1	Yes
   (d)	[Ag(NH₃)Cl]Cl	x - 1 = +1, so +2	No

3. So. The precipitate dissolves as diamminesilver(I) chloride, [Ag(NH₃)₂]Cl, which is option (c).

The idea to keep. A precipitate dissolves in a complexing agent when the complex binds the metal ion more tightly. The metal keeps its oxidation state, and Ag⁺ forms linear [Ag(L)₂]⁺.

Answer from the NTA final answer key. Solution by PrepWiser.