Heterogeneous Equilibrium

The equation of self-ionization of water :
H2O(l) ⇌ H^+(aq) + OH^-(aq)

This is a homogeneous equilibrium, because all the components involved are in"one single phase" (aqueous phase)only.

A substance is in aqueous state when this substance is dissolved in water.

For pure water, it is in liquid state and not aqueous state.

actually , what do you mean as "aqueous state"?

when a compound dissolve in water it is surrounded by water molecules
however, water molecule itself is also surrounded by water molecules when in liquid state, it is also in "aqueous" state!

is there any additional information??like catalyst,medium,solvent.....