What is the exact fraction (degree of dissociation, ) of pure water molecules that are ionized at ? — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The degree of dissociation $\alpha = \frac{\text{moles dissociated}}{\text{total initial moles}}$. The concentration of dissociated water equals $[H^+] = 10^{-7} \text{ M}$. The initial concentration of pure water is $55.5 \text{ M}$. Thus, $\alpha = \frac{10^{-7}}{55.5} = 1.8 \times 10^{-9}$.