The question requires us to identify the spectator ions for the following chemical reaction:
[tex]\text{NiS}_{(s)}+2HCl_{(aq)}\to NiCl_{2(aq)}+H_2S_{(g)}[/tex]
To answer the question, we need to write the net ionic reaction.
The reaction with the ionic species, considering only those molecules in aqueous medium, would be:
[tex]\text{NiS}_{(s)}+2H^++2Cl^-\to Ni^{2+^{}}+2Cl^-_{}+H_2S_{(g)}[/tex]
Note that we can "eliminate" the ions Cl- because there is the same amount of it on both sides of the equation:
[tex]\text{NiS}_{(s)}+2H^+\to Ni^{2+^{}}+H_2S_{(g)}[/tex]
Therefore, since the ions Cl- can be eliminated and are not part of the net ionic equation, they are the spectator ions for this chemical reaction.
