Question

Which equation best represents the dissociation of water molecules into hydrogen ions and hydroxide ions?


H2O → H O+ + H–

(it's not supposed to have a space, it was just flagged if put together)


H2O – OH– → H+


H2O – H+ → OH–


H2O → H+ + OH–

Answer 1

it is H2O ----> H+ + OH-

Answer 2

Answer is: H₂O → H⁺ + OH⁻.

Water dissociates (autoionization) to form hydrogen ions (H⁺) and hydroxide (OH⁻) ions. The protons (H⁺) hydrate as hydroxonium ions( H₃O⁺).

The Kw (the ionic product for water) at 25°C is 1·10⁻¹⁴ mol²/dm⁶ or 1·10⁻¹⁴ M². Concentration of hydrogen ions and hydroxide ions in pure water are the same.