Chemistry Electrochemistry UHS 2024
PMDC Verified Question 3 of 73
Which of the following is NOT a correct feature of electrolytic cells?
A
Reduction occurs at cathode
B
Oxidation occurs at anode
C
Alternating current source is connected to electrodes
D
Electrochemical reaction takes place
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Alternating current source is connected to electrodes
Concept:

An electrolytic cell uses an external power supply to drive a non-spontaneous chemical reaction by forcing electrons in a single, specific direction.

Solution:

  • Because specific half-reactions must occur at designated electrodes (oxidation at the anode, reduction at the cathode), the polarity of the electrodes must remain strictly constant.


  • This requires a Direct Current (DC) source, like a standard battery.


  • If an Alternating Current (AC) source were used, the polarity of the electrodes would rapidly switch back and forth (e.g., 50 times a second), causing the redox reactions to constantly reverse themselves and resulting in zero net electrolysis.


Why other options are incorrect:

Options A, B, and D are fundamental, true characteristics of all electrochemical cells.

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