Self-Ionisation of Water (Leaving Cert Chemistry): Flashcards

Water molecules react to form $H_3O^+$ and $OH^-$ ions

Hydronium ion ($H_3O^+$) and hydroxide ion ($OH^-$)

Dynamic equilibrium

Ionic product of water / equilibrium constant

$K_w = [H^+][OH^-]$

$1.0 \times 10^{-14}$ mol$^2$ dm$^{-6}$

They are equal

$1.0 \times 10^{-7}$ mol dm$^{-3}$

7

$K_w$ increases as temperature increases

Self-ionisation is endothermic

Yes, remains neutral because $[H^+]$ still equals $[OH^-]$

$\text{pH} = -\log[H^+]$

$[H^+] = \sqrt{K_w}$