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

May 14, 2017

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

#### Explanation:

$C {r}_{2} {O}_{7}^{2 -} + 14 {H}^{+} + 6 {e}^{-} \rightarrow 2 C {r}^{3 +} + 7 {H}_{2} O$ $\left(i\right)$

And $P {b}^{2 +}$ may be oxidized to $P {b}^{4 +}$....

$P {b}^{2 +} \rightarrow P {b}^{4 +} + 2 {e}^{-}$ $\left(i i\right)$

And so add $\left(i\right) + 3 \times \left(i i\right)$ to give.............

$C {r}_{2} {O}_{7}^{2 -} + 14 {H}^{+} + 3 P {b}^{2 +} \rightarrow 2 C {r}^{3 +} + 3 P {b}^{4 +} + 7 {H}_{2} O$

And if this redox couple works, and I have no idea whether it does, we would have to use $3.34 \cdot m o l$ dichromate ion........