Chemistry Electrochemistry PMC 2021
PMDC Verified Question 39 of 73
The least reactive transition metal:
A
Zn
B
Sc
C
Cu
D
Au
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Au
Concept:

The chemical reactivity of a metal is tied to its willingness to lose electrons (oxidation potential). Metals with very high positive reduction potentials are extremely resistant to oxidation.

Solution:

  • Gold (Au) sits at the very bottom of the standard electrochemical series.


  • It has an exceptionally high standard reduction potential (\( Au^{+3} / Au \approx +1.50 \text{ V} \)).


  • This implies that Gold has virtually zero tendency to spontaneously lose electrons to the environment, making it a highly inert, noble metal.


Why other options are incorrect:

Scandium and Zinc have highly negative reduction potentials, making them very reactive. Copper is less reactive than Zn but far more reactive than Gold.

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