VITEEE 2018 Paper

In the silver plating of copper, K[Ag(CN)2] is used instead of AgNO3. Copper being more electropositive readily precipitate silver from their salt solution
Cu + 2AgNO3 → Cu(NO3)−2 + Ag
whereas in K[Ag(CN)2] solution a complex anion [Ag(CN)2]− is formed and hence Ag+ are less available in the solution and therefore copper cannot displace Ag from its complexion.