The electrode with reaction `:Cr_(2)O_(7)^(2-)(aq)+14H^(o+)(aq)+6e^(-) rarr 2Cr^(3+)(aq)+7H_(2)O` can be represented as

Options

A. `Pt|H^(o+)(aq),Cr_(2)O_(7)^(2-)(aq)`
B. `Pt|H^(o+)(aq),Cr_(2)O_(7)^(2-)(aq),Cr^(3+)(aq)`
C. `Pt_(H2)|H^(o+)(aq),Cr_(2)O_(7)^(2-)`
D. `Pt_(H2)|H^(o+)(aq),Cr_(2)O_(7)^(2-)(aq),Cr^(3+)(aq)`

Answer

d

Explanation

`Cr_(2)O_(7)^(2-)` reduces to `2Cr^(3+)`, so much be represented at cathode. `H_(2)` is oxidized to `2H^(o+)`, so must be representedd at anode. So the cell representation is as shown in `(d)`.