Chemistry Electrochemistry PMDC 2020
PMDC Verified Question 45 of 73
During oxidation process, oxidation number of an element:
A
Decreases
B
Increases
C
Remains constant
D
Both "A" and "B"
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Increases
Concept:

Oxidation is fundamentally defined as the loss of electrons from an atom, ion, or molecule.

Solution:

  • Because electrons carry a negative electrical charge, removing them causes the chemical species to become more mathematically positive.


  • For example, when solid Zinc oxidizes, it loses two electrons: \( Zn \rightarrow Zn^{+2} + 2e^- \).


  • The oxidation number moves from \( 0 \) to \( +2 \), which is a numerical increase.


Why other options are incorrect:

A decrease in oxidation number corresponds to the gain of electrons, which is strictly defined as reduction.

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