Chemistry Electrochemistry MDCAT 2015
PMDC Verified Question 70 of 73
Keeping in mind the electrode potential, which one of the following reactions is feasible?
A
\( Zn^{+2} + Cu \rightarrow Cu^{+2} + Zn \)
B
\( Fe + CuSO_4 \rightarrow FeSO_4 + Cu \)
C
\( Zn + MgSO_4 \rightarrow ZnSO_4 + Mg \)
D
\( Cd + MgSO_4 \rightarrow CdSO_4 + Mg \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( Fe + CuSO_4 \rightarrow FeSO_4 + Cu \)
Concept:

A metal can displace another metal from its aqueous salt solution only if it sits "higher" (has a more negative reduction potential) in the electrochemical series.

Solution:

  • Iron (Fe) has a standard reduction potential of \( -0.44 \text{ V} \), whereas Copper (Cu) has a potential of \( +0.34 \text{ V} \).


  • Because Fe is a stronger reducing agent than Cu, solid Iron will easily oxidize and displace Copper ions from the sulfate solution.


  • The reaction \( Fe + CuSO_4 \rightarrow FeSO_4 + Cu \) is highly spontaneous and feasible.


Why other options are incorrect:

In option A, Cu cannot displace Zn. In option C, Zn cannot displace Mg (Mg is highly reactive). In option D, Cd cannot displace Mg.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Electrochemistry MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App