1. From the following ionic equations below, put a tick (✓) if there is a reaction taking place and an x if there is no reaction taking place.
a. [tex]Zn ^{2+}( aq )+ Fe ( s ) \longrightarrow Fe ^{2+}(\frac{ aq }{ a })+ Zn ( s )[/tex]
b. [tex]Mg ^{2+}( aq )+ Zn ( s ) \longrightarrow Zn ^{2+}( aq )+ Mg ( s )[/tex]
c. [tex]Fe ^{2+}( aq )+ Zn ( s ) \longrightarrow Zn ^{2+}( aq )+ Fe ( s )[/tex]
d. [tex]Pn ^{2+}( aq )+ Cu ( s ) \longrightarrow Cu ^{2+}( aqu ) ! Pu ( s )[/tex]
e. [tex]Cu ^{2+}( aq )+ Fe ( s ) \longrightarrow Fe ^{2+}( aq )+ Cu ( s )[/tex]
2. Define spectator ion.
Answer (1)
Reaction a: No reaction occurs as Fe is less reactive than Zn.
Reaction b: No reaction occurs as Zn is less reactive than Mg.
Reaction c: Reaction occurs as Zn is more reactive than Fe.
Reaction d: No reaction occurs as Cu is less reactive than Pb.
Reaction e: Reaction occurs as Fe is more reactive than Cu.
Spectator ion: An ion that remains unchanged during a reaction.
Explanation
Problem Analysis We are given five ionic equations and asked to determine if a reaction will occur in each case. To do this, we will use the electrochemical series (reactivity series) to compare the relative ease of oxidation of the metals involved. A reaction will occur if the solid metal is higher in the series (more easily oxidized) than the metal ion in solution. We also need to define a spectator ion.
Reaction a a. Z n 2 + ( a q ) + F e ( s ) ⟶ F e 2 + ( a q ) + Z n ( s ) :
Iron (Fe) is the solid metal, and Zinc ion ( Z n 2 + ) is in solution.
According to the reactivity series, Iron (Fe) is lower than Zinc (Zn). This means Zinc is more easily oxidized than Iron, so Iron cannot displace Zinc ions from the solution. Therefore, no reaction takes place.
Reaction b b. M g 2 + ( a q ) + Z n ( s ) ⟶ Z n 2 + ( a q ) + M g ( s ) :
Zinc (Zn) is the solid metal, and Magnesium ion ( M g 2 + ) is in solution.
According to the reactivity series, Zinc (Zn) is lower than Magnesium (Mg). This means Magnesium is more easily oxidized than Zinc, so Zinc cannot displace Magnesium ions from the solution. Therefore, no reaction takes place.
Reaction c c. F e 2 + ( a q ) + Z n ( s ) ⟶ Z n 2 + ( a q ) + F e ( s ) :
Zinc (Zn) is the solid metal, and Iron ion ( F e 2 + ) is in solution.
According to the reactivity series, Zinc (Zn) is higher than Iron (Fe). This means Zinc is more easily oxidized than Iron, so Zinc can displace Iron ions from the solution. Therefore, a reaction takes place.
Reaction d d. P b 2 + ( a q ) + C u ( s ) ⟶ C u 2 + ( a q ) + P b ( s ) :
Copper (Cu) is the solid metal, and Lead ion ( P b 2 + ) is in solution. Assuming the typo is corrected from Pn to Pb.
According to the reactivity series, Copper (Cu) is lower than Lead (Pb). This means Lead is more easily oxidized than Copper, so Copper cannot displace Lead ions from the solution. Therefore, no reaction takes place.
Reaction e e. C u 2 + ( a q ) + F e ( s ) ⟶ F e 2 + ( a q ) + C u ( s ) :
Iron (Fe) is the solid metal, and Copper ion ( C u 2 + ) is in solution.
According to the reactivity series, Iron (Fe) is higher than Copper (Cu). This means Iron is more easily oxidized than Copper, so Iron can displace Copper ions from the solution. Therefore, a reaction takes place.
Spectator Ion Definition A spectator ion is an ion that exists in the same form on both the reactant and product sides of a chemical equation. These ions do not participate in the reaction and are not included in the net ionic equation.
Final Answer Here's the summary of whether a reaction takes place: a. No reaction b. No reaction c. Reaction d. No reaction e. Reaction
Spectator Ion: An ion that does not participate in the reaction and remains unchanged in the solution.
Examples
Understanding the reactivity series and displacement reactions is crucial in various real-world applications, such as designing corrosion-resistant materials. For example, coating iron with a more reactive metal like zinc (galvanization) prevents rusting because zinc will corrode first, protecting the iron underneath. Similarly, this knowledge helps in the extraction of metals from their ores, where a more reactive metal is used to displace a less reactive metal from its compound.
