Final answer:
The net ionic equation for the reaction Cu(NO₃)₂ + K₂S = CuS + 2KNO₃ is Cu²⁺ + S²⁻ = CuS.
Step-by-step explanation:
The net ionic equation for the reaction Cu(NO₃)₂ + K₂S = CuS + 2KNO₃ is option a) Cu²⁺ + S²⁻ = CuS. To determine the net ionic equation, we need to first write the balanced molecular equation and then break it down into its ionic forms. In the molecular equation, Cu²⁺ and S²⁻ ions combine to form CuS, while K⁺ and NO₃⁻ ions remain as their individual ions. Canceling out the spectator ions (K⁺ and NO₃⁻), we are left with the net ionic equation Cu²⁺ + S²⁻ = CuS.