Question

why the solution of silver nitrate becomes blue in colour after sometime when copper turning are added to it.

Answer 1

the solution of silver nitrate turns blue as we add copper as copper is more reactive than silver and hence it displaces the silver and forms copper nitrate which has blue color

Answer 2

when Cu turnings are added to AgNO3 solution , the solution becomes Blue in colour after sometime... because Cu is more reactive than Ag so it displaces Ag from AgNO3 solution and forms Cu(NO3)2