Question

How do you balance `Cr(s) + Fe(NO_3)_2(aq) -> Fe(s) + Cr(NO_3)_3(aq)`?

Answer 1

Write the individual redox equations........

Explanation:

Chromium metal is oxidized..........

`Cr(s) rarrCr^(3+) +3e^(-)` `(i)`

And `Fe^(2+)` is reduced...........

`Fe^(2+) +2e^(-) rarr Fe(s)` `(ii)`

And we cross multiply to multiply to remove the electrons: `2xx(i)+3xx(ii):`

`3Fe^(2+)+2Cr(s) rarr 3Fe(s)+2Cr^(3+)`

And if you like, you can add in some nitrate ions........

`3Fe(NO_3)_2+2Cr(s) rarr 3Fe(s)+2Cr(NO_3)_3(aq)`