Chemistry Electrochemistry ETEA 2023
PMDC Verified Question 20 of 73
Zinc displaces copper from its solution because:
A
Atomic no. of zinc is higher than that of copper
B
Zinc has higher reduction potential than copper
C
Zinc is more soluble
D
Zinc has smaller reduction potential than copper
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Zinc has smaller reduction potential than copper
Concept:

A metal can spontaneously displace another metal from its aqueous salt solution if it acts as a stronger reducing agent.

Solution:

  • The strength of a reducing agent is inversely proportional to its reduction potential. A smaller (more negative) reduction potential means a higher tendency to lose electrons (oxidize).


  • Zinc has a standard reduction potential of \( -0.76 \text{ V} \).


  • Copper has a standard reduction potential of \( +0.34 \text{ V} \).


  • Because Zinc has a smaller reduction potential than Copper, solid Zinc will naturally oxidize, forcing the Copper ions in solution to reduce and precipitate out.


Why other options are incorrect:

Option B is factually inverted (Zinc's potential is lower, not higher). Atomic number and general solubility are not the primary thermodynamic drivers for redox displacement.

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