In a disproportionation reaction, same substance
undergoes oxidation (increase in oxidation number)
and reduction (decrease in oxidation number
forming two different products.
3
NEET 2018
MCQ (Single Correct Answer)
The correct order of N-compounds in its
decreasing order of oxidation states is
Consider the change in oxidation state of
bromine corresponding to different emf values
as shown in the given diagram :
Then the species undergoing disproportionation
is :
A
BrO4–
B
BrO3–
C
Br2
D
HBrO
Explanation
Calculate Eocell corresponding to each
compound undergoing disproportionation
reaction. The reaction for which Eocell comes
out + ve is spontaneous.
HBrO $$ \to $$ Br2, EoHBrO/Br2 = 1.595 V
HBrO $$ \to $$ BrO3–, EoBrO3-/HBrO = 1.595 V
Eocell for the disproportionation of HBrO,
Eocell = EoHBrO/Br2 - EoBrO3-/HBrO
= 1.595 - 1.5
= 0.095 V = + ve
So, Eocell > 0
So, $$\Delta $$Go < 0 (Spontaneous)
Questions Asked from Redox Reactions
On those following papers in MCQ (Single Correct Answer)
Number in Brackets after Paper Indicates No. of Questions