Question

How many moles of dichromate ion are necessary to oxidize `10*mol` of `Pb^(2+)` ion to `Pb^(4+)` ion?

Answer 1

Well, we need to write the redox equation............

Explanation:

`Cr_2O_7^(2-) +14H^+ + 6e^(-)rarr 2Cr^(3+) +7H_2O` `(i)`

And `Pb^(2+)` may be oxidized to `Pb^(4+)`....

`Pb^(2+) rarr Pb^(4+) + 2e^-` `(ii)`

And so add `(i) + 3xx(ii)` to give.............

`Cr_2O_7^(2-) +14H^+ + 3Pb^(2+)rarr 2Cr^(3+) +3Pb^(4+) + 7H_2O`

And if this redox couple works, and I have no idea whether it does, we would have to use `3.34*mol` dichromate ion........