Chemistry Electrochemistry MDCAT 2010
PMDC Verified Question 73 of 73
In an electrochemical series, elements are arranged on the basis of:
A
pH scale
B
pKa scale
C
pOH scale
D
Hydrogen scale
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Hydrogen scale
Concept:

The electrochemical series is a systematic arrangement of elements based on their standard electrode potentials.

Solution:

  • All standard electrode potentials are measured relative to a universal reference point.


  • This reference is the Standard Hydrogen Electrode (SHE), which is arbitrarily assigned a potential of exactly \( 0.00 \text{ V} \).


  • Therefore, the series is fundamentally arranged on the basis of the "Hydrogen scale" (increasing or decreasing standard reduction potential relative to Hydrogen).


Why other options are incorrect:

pH, pOH, and pKa scales are used to measure the acidity, basicity, or dissociation constants of chemical species in solution, not their standard redox potentials.

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