Question

1) How can AgCl(s) be dissolved completely?

a) Write an equation for this reation.

Answer 1

Agcl(s) is completely dissolved either in NH3 / HCl .

Silver acts as a Lewis acid and so it can react with HCl to form the soluble anionic species [AgCl2]^- or [Ag(NH3)2]+ where chloride is solvated by ammonia and water and removed from the metal sphere.

Adding HCl to [Ag(NH3)2]+ reduces the concentration of NH3 due to protonation:

NH3(aq) + H+(aq) ---> [NH4]+(aq)

While adding NH3 to a solution containing [AgCl2]^- is depleted the same way as discussed above and NH3 does not change the concentration of Cl- in solution, unless the volumes are different for same amount of silver ion present.

The reaction is under below

AgCl(s) + 2NH3(aq) ==>Ag(NH3)2Cl(aq) ==> Ag(NH3)2⁺(aq) + Cl^-(aq)