# Why don't we write K(s) + 2H_2O(l)rarr K(OH)_2(aq) + 1/2H_2(g)?

May 24, 2017

Because it does not follow the experiment.............

#### Explanation:

$\text{Potassium metal}$ is oxidized by water to give $\text{potassium hydroxide}$ and $\text{dihydrogen gas}$:

$K \left(s\right) + {H}_{2} O \left(l\right) \rightarrow K O H \left(a q\right) + \frac{1}{2} {H}_{2} \left(g\right) \uparrow$

And given the experiment, we would find half an equiv of dihydrogen gas evolved per equiv of metal, and one equiv of hydroxide in solution. Both results could be easily confirmed by experiment.

A species such $K {\left(O H\right)}_{2}$ is UNKNOWN............and is likely to remain unknown given that it contains a ${K}^{2 +}$ species, an unknown ion.