# Why does zinc increase in mass after being placed in NaOH?

Jun 28, 2017

Because of formation of the zincate species, ${\left[Z n {\left(O H\right)}_{4}\right]}^{2 -}$...

#### Explanation:

Zinc metal is quite active, and can be oxidized under either acidic or basic conditions......

$\text{Oxidation.....:}$

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

$\text{Reduction.....:}$

${H}_{2} O + {e}^{-} \rightarrow \frac{1}{2} {H}_{2} \uparrow + H {O}^{-}$

$\text{Overall.....}$

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