Changes in Oxidation States

Consider reactions 1 through 6. Those carbon atoms undergoing change, as part of a functional group, are colored (red and blue). In the cases shown, each carbon atom has either been reduced or oxidized. Your job is to identify the change in oxidation state that has occurred for each of the colored carbons.

Reaction Red Carbon Blue Carbon
1. CH3CH=CH2 Br2

 
CH3CHBrCH2Br Reduced
Oxidized
Reduced
Oxidized
2. CH3CH=CH2 (i) B2H6

(ii) H2O2 , NaOH
CH3CH2CH2OH Reduced
Oxidized
Reduced
Oxidized
3. CH3CH2CH=O NaBH4

 
CH3CH2CH2OH Reduced
Oxidized
 
4. CH3CH2CH=O Ag(+)

H2O , pH>8
CH3CH2CO2H Reduced
Oxidized
 
5. CH3COCH2CO2H Heat

 
CH3COCH3
+
O=C=O
Reduced
Oxidized
Reduced
Oxidized
6. H2C=C(OH)C2H5 tautomerization

 
H3CCOC2H5 Reduced
Oxidized
Reduced
Oxidized

   

This script written by William Reusch, Dept. of Chemistry, Michigan State University. Please send comments and corrections to whreusch@pilot.msu.edu.