# What redox reaction occurs between MnO_2 and HCl?

Aug 6, 2017

Try........

$M n {O}_{2} \left(s\right) + 4 {H}^{+} + 2 C {l}^{-} \rightarrow M {n}^{2 +} + 2 {H}_{2} O \left(l\right) + C {l}_{2} \left(g\right)$

#### Explanation:

Manganese oxide is reduced to colourless $M {n}^{2 +}$:

$M n {O}_{2} \left(s\right) + 4 {H}^{+} + 2 {e}^{-} \rightarrow M {n}^{2 +} + 2 {H}_{2} O \left(l\right)$ $\left(i\right)$

Chloride ion is oxidized to $C {l}_{2}$ gas:

$C {l}^{-} \rightarrow \frac{1}{2} C {l}_{2} \left(g\right) + {e}^{-}$ $\left(i i\right)$

And so we add the equations together in a way such that the electrons are cancelled: $\left(i\right) + 2 \times \left(i i\right)$ gives........

$M n {O}_{2} \left(s\right) + 4 {H}^{+} + 2 C {l}^{-} \rightarrow M {n}^{2 +} + 2 {H}_{2} O \left(l\right) + C {l}_{2} \left(g\right)$

Alternatively.........

$M n {O}_{2} \left(s\right) + 2 {H}^{+} + 2 H C l \left(a q\right) \rightarrow M {n}^{2 +} + C {l}_{2} \left(g\right) + 2 {H}_{2} O \left(l\right)$

or.............

$M n {O}_{2} \left(s\right) + 4 H C l \left(a q\right) \rightarrow M n C {l}_{2} \left(a q\right) + C {l}_{2} \left(g\right) + 2 {H}_{2} O \left(l\right)$