Chemistry Electrochemistry BUMHS 2024
PMDC Verified Question 12 of 73
Oxidation number of "Mn" in \( KMnO_4 \) is:
A
+4
B
+5
C
+6
D
+7
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: +7
Concept:

The oxidation states of all atoms in a neutral molecule must sum to zero.

Formula:

$$+1 + x + 4(-2) = 0$$

Solution:

  • Potassium (K) is always \( +1 \). Oxygen (O) is \( -2 \).


  • Let \( x \) be the oxidation state of Manganese (Mn).


  • \( 1 + x - 8 = 0 \implies x - 7 = 0 \implies x = +7 \).


Why other options are incorrect:

If one forgot the Potassium atom, they might calculate \( +8 \). If they miscalculated Oxygen, they might guess \( +4 \) or \( +6 \). \( +7 \) is mathematically precise.

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