Which is stronger oxidizing agent
(i). `K_(2)Cr_(2)O_(7)` in solution in which
`[Cr_(2)O_(7)^(2-)]=0.1M,[Cr^(3+)]=10^(-2)M` and `[H^(+)]=10^(-1)M`
(ii). `KMnO_(4)` in a solution in which
`[MnO_(4)^(-)]=10^(-1)M,[Mn^(2+)]=10^(-2)M,[H^(+)]=10^(-2)M`
`E_(Cr_(2)O_(7)^(2-)//Cr^(+3))^(0)=1.33V,E_(MnO_(4)^(-)//Mn^(+2))^(0)=1.51V`

Explanation

(i). `14H^(+)+Cr_(2)O_(7)^(2-)to2Cr^(+3)+7H_(2)O+6e^(-)`
`E_(Red^(n))=1.33-(0.059)/(6)log[(10^(-4)xx10)/(10^(-14))]=1.33-(0.059)/(6)xx11`
`E_(Red^(n))=1.33-(0.649)/(6)=1.330-0.108=1.222V`
(ii). `5e^(-)+8H^(+)+MnO_(4)^(-)toMn^(2+)+4H_(2)O`
`E_(Red^(n))=1.51-(0.059)/(5)log[(10^(-2))/(10^(-16)xx10^(-1))]=1.51-0.059xx3=1.51-0.18=1.33V`
`E_(Red^(n))` is more so, good oxidising agent