The number of moles of electron required to reduce 0.2 mole of `Cr_(2)O_(7)^(2-)` to `Cr^(3+)`

Options

A. `1.2`
B. 6
C. 12
D. `0.6`

Answer

A

Explanation

(a): `overset(+6)Cr_(2)O_(7)^(2-)+6e^(-) to 2Cr^(3+)`
Change in oxidation state = +3 per chromium atom.
1 mole of `Cr_(2)O_(7)^(2-)` required = `6e^(-)`
`:.` 0.2 moles of Cr required = `0.2xx6=1.2` moles of `e^(-)s`