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

May 15, 2017

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

#### Explanation:

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

$C r \left(s\right) \rightarrow C {r}^{3 +} + 3 {e}^{-}$ $\left(i\right)$

And $F {e}^{2 +}$ is reduced...........

$F {e}^{2 +} + 2 {e}^{-} \rightarrow F e \left(s\right)$ $\left(i i\right)$

And we cross multiply to multiply to remove the electrons: $2 \times \left(i\right) + 3 \times \left(i i\right) :$

$3 F {e}^{2 +} + 2 C r \left(s\right) \rightarrow 3 F e \left(s\right) + 2 C {r}^{3 +}$

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

$3 F e {\left(N {O}_{3}\right)}_{2} + 2 C r \left(s\right) \rightarrow 3 F e \left(s\right) + 2 C r {\left(N {O}_{3}\right)}_{3} \left(a q\right)$