What are the oxidation and reduction equations for the following equations: Zn(s) + 2H2O(l) → Zn(OH)2(s) + H2(g) ?

Jul 10, 2017

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

Explanation:

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

Hydrogen ion, as the $\text{acidium ion}$ in water is commonly represented as ${H}_{3} {O}^{+}$, or even, more simply as ${H}^{+}$. Let's take the former..........

${H}_{3} {O}^{+} + {e}^{-} \rightarrow \frac{1}{2} {H}_{2} \left(g\right) + {H}_{2} O \left(l\right)$ $\left(i i\right)$

We add the individual redox equations in such a way that electrons do NOT appear.........i.e. $\left(i\right) + 2 \times \left(i i\right)$

$Z n \left(s\right) + 2 {H}_{3} {O}^{+} \rightarrow Z {n}^{2 +} + 2 {H}_{2} O \left(l\right) + {H}_{2} \left(g\right) \uparrow$

Charge is balanced, and mass is balanced, as is required for any stoichiometric equation...........any representation of reality.