Question

In the reaction given below which species is called a spectator ion and why: $Zn(s)+Cu^{2+}(aq)+SO_{4}^{2-}(aq)$→$Zn^{2+}(aq)+Cu(s)+SO_{4}^{2-}(aq)$

Answer 1

Given, the reaction,

$Zn(s)+Cu^{2+} (aq)+(SO_4 )^{2-}  (aq)\rightarrow Zn^{2+} (aq)+Cu(s)+(SO_4 )^{2-}  (aq)$

A spectator ion is an ion that exists in the same form on both the reactant and product sides of a chemical reaction. Spectator ions may be either cations or anions.

The  Sulfate ion $(SO_4 )^{2-}$ is the spectator ions in this reaction. It is not changed in both the product and reactant side of the equation.

The sulfate ions just 'spectate' while Zn ends the reaction as $n^{2+}$, loses the  2 electrons and Cu gains two electrons.