Oxidation numbers are always while numbers and must be always calculated on the basis of their structures and never from their molecular formulae. Redox reactants may involve combination of atoms/molecules, decomposition of substances, displacement of metals of non metals and disproportionation of a particular species which may be metals, non-metals or ions. Redox reactions can be balanced both by oxidation number method as well as by ion electron method.
For the redox reaction `xMnO_(4)^(-)+yC_(2)O_(4)^(2-)+zH^(+)rarrx,y and z` are
A. `”2 5 16″`
B. `”16 5 2″`
C. `”5 16 2″`
D. `”2 16 5″`
Correct Answer – A
The balanced redox reaction is
`2MnO_(4)^(-)+5C_(2)O_(4)^(2-)+16H^(+)rarr2Mn^(2+)+10CO_(2)+8H_(2)O`
Thus the coefficients of `MnO_(4)^(-), C_(2)O_(4)^(2-) and H^(+)` respectively are 2,5 and 16.