Chemistry Electrochemistry BUMHS 2022
PMDC Verified Question 35 of 73
What is the oxidation number of \( Cl_2 \)?
A
0
B
+1
C
-1
D
-2
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 0
Concept:

The oxidation number indicates the degree of oxidation (electron loss/gain). In a homonuclear diatomic molecule, bonding electrons are shared perfectly equally.

Solution:

  • Chlorine gas (\( Cl_2 \)) consists of two identical Chlorine atoms covalently bonded together.


  • Because both atoms possess the exact same electronegativity, neither atom can pull electron density away from the other.


  • Consequently, there is zero net charge transfer. By universal IUPAC convention, any element in its free elemental state is assigned an oxidation number of \( 0 \).


Why other options are incorrect:

Chlorine only exhibits \( -1 \) when it successfully bonds with a less electronegative element (like Na) to form an ionic or polar covalent bond.

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