Concept:A spontaneous redox reaction occurs when a metal with a higher oxidation potential displaces a metal with a lower oxidation potential from its solution.
Solution:- The given values are standard oxidation potentials (notice the reactions show the loss of electrons).
- Zinc has a much higher oxidation potential (\( +0.76 \text{ V} \)) than Copper (\( -0.34 \text{ V} \)).
- Therefore, solid Zinc will spontaneously oxidize into \( Zn^{+2} \), and aqueous \( Cu^{+2} \) will be forced to undergo reduction into solid Copper.
- The spontaneous overall reaction is: \( Zn_{(s)} + Cu^{+2}_{(aq)} \rightarrow Zn^{+2}_{(aq)} + Cu_{(s)} \).
Why other options are incorrect:Option A represents the reverse (non-spontaneous) reaction. Options C and D show fundamentally impossible redox stoichiometry where both species undergo reduction.
Note on Signs: Standard reduction potentials are \( E^\circ_{\text{red}}(\text{Zn}) = -0.76\text{ V} \) and \( E^\circ_{\text{red}}(\text{Cu}) = +0.34\text{ V} \). Because the half-reactions in the question prompt depict electron loss (oxidation), the values given are standard oxidation potentials (\( +0.76\text{ V} \) and \( -0.34\text{ V} \)).
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