What are the spectator ions in #Mg(s) + Zn^(2+) + 2NO_3^(-) -> Mg^(2+) + 2NO_3^(-) + Zn(s)#?
1 Answer
The nitrate anions,
Explanation:
A spectator ion is an ion that is present on both sides of a chemical equation.
In other words, in order for an ion to be a spectator ion, it must exist as such as a reactant and as a product in the balanced chemical equation.
You're dealing with a single replacement reaction in which magnesium metal,
The products of this reaction are zinc metal,
The problem provides you with the complete ionic equation for this reaction
#"Mg"_ ((s)) + "Zn"_ ((aq))^(2+) + 2"NO"_ (3(aq))^(-) -> "Mg"_ ((aq))^(2+) + 2"NO"_ (3(aq))^(-) + "Zn"_ ((s))#
As you can see, the reactants' side contains two ions
- the zinc cation,
#"Zn"^(2+)# - the nitrate anion,
#"NO"_3^(2-)#
Likewise, the product's side also contains two ions
- the magnesium cation,
#"Mg"^(2+)# - the nitrate anion,
#"NO"_3^(-)#
Because the nitrate anions are present on both sides of the equation, they are spectator ions.
This means that you can eliminate them from the complete ionic equation
#"Mg"_ ((s)) + "Zn"_ ((aq))^(2+) + color(red)(cancel(color(black)(2"NO"_ (3(aq))^(-)))) -> "Mg"_ ((aq))^(2+) + color(red)(cancel(color(black)(2"NO"_ (3(aq))^(-)))) + "Zn"_ ((s))#
to get the net ionic equation
#"Mg"_ ((s)) + "Zn"_ ((aq))^(2+) -> "Mg"_ ((aq))^(2+) + "Zn"_ ((s))#
