To understand why the given single replacement reaction is also a redox reaction, we'll need to analyze the changes in oxidation states of the elements involved. The reaction given is:
[tex]\[ Cu + 2 AgNO_3 \rightarrow Cu(NO_3)_2 + 2 Ag \][/tex]
### Step-by-Step Solution:
1. Identify the Reactants and Products:
- Reactants: Copper (Cu) and Silver Nitrate (AgNO₃)
- Products: Copper(II) Nitrate (Cu(NO₃)₂) and Silver (Ag)
2. Determine Oxidation States:
- Copper (Cu): As a pure element, the oxidation state of copper in [tex]\( Cu \)[/tex] is 0.
- Silver (Ag): In the compound [tex]\( AgNO_3 \)[/tex], silver has an oxidation state of +1. In the product, as a pure metal, silver (Ag) has an oxidation state of 0.
- Nitrate Ion (NO₃⁻) is a polyatomic ion where nitrogen typically has an oxidation state of +5 and oxygen an oxidation state of -2.
3. Changes in Oxidation States:
- Copper Changes:
- Reactant: [tex]\( Cu^0 \)[/tex]
- Product: In [tex]\( Cu(NO_3)_2 \)[/tex], copper is in the +2 oxidation state ([tex]\( Cu^{2+} \)[/tex]).
- This indicates copper is oxidized: [tex]\( Cu^0 \rightarrow Cu^{2+} \)[/tex] (loss of 2 electrons).
- Silver Changes:
- Reactant: In [tex]\( AgNO_3 \)[/tex], silver has an oxidation state of +1.
- Product: [tex]\( Ag^0 \)[/tex] (pure silver metal).
- This indicates silver is reduced: [tex]\( Ag^+ \rightarrow Ag^0 \)[/tex] (gain of 1 electron).
4. Identify the Redox Process:
- Oxidation: Copper is going from [tex]\( Cu^0 \)[/tex] to [tex]\( Cu^{2+} \)[/tex] (losing electrons).
- Reduction: Silver is going from [tex]\( Ag^+ \)[/tex] to [tex]\( Ag^0 \)[/tex] (gaining electrons).
### Conclusion:
The evidence that the single replacement reaction is also a redox reaction is:
Silver is in a compound as a reactant, but is a pure element as a product.
In simpler terms, the observed changes in oxidation states (Copper being oxidized and Silver being reduced) explicitly indicate a redox process. Thus, this change in the form of silver illustrates that a redox reaction has taken place.
