Question

The reduction potential diagram for `Cu` in acid solution is :

Calculate `X`. Does `Cu^(+)` disproportionate in solution ?

Answer 1

Correct Answer - `x=0.325"volt":Cu^(+)` disproportionates since `Cu^(+)` behave both as a self reducing and a self oxidising agent.
`Cu^(2+)+e^(-)toCu^(2+)" "E^(@)=0.15" "triangleG^(@)=-Fxx0.15`
`underline(Cu^(2+)+2e^(-)toCu" "E^(@)=0.50" "triangleG^(@)=-Fxx0.50)`
`Cu^(2+)+2e^(-)toCu" "triangleG^(@)=-Fxx0.65`
`=-2xxFxxE_(Cu^(2+)//Cu)^(@)`
`E_(Cu^(2+)//Cu)^(@)=0.325`
`Cu^(+)+Cu^(+)toCu^(2+)+Cu`
`E_(cell)^(@)=0.5-0.15=0.35"volt"`
So, disproportionation is possible.