The spectator ions that remain in solution are potassium ion and nitrate ion.
The spectator ions are the ions that remain in solution after reaction. They are those ions that are unchanged at the end of the reaction. For the reaction of Cu(NO3)2 and K2S, teh products are CuS and KNO3.
As such the spectator ions that remain in solution are potassium ion and nitrate ion.
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