Question

what is the difference between dissociation and ionisation?

Answer 1

dissociation means complete dissolving of atoms
ionisation means when ions are formed

Answer 2

When covalent compounds dissolve in water to produce ions, the dissociation process is often called ionization. Ionisation is the process that involves the formation of ions whereas dissociation is the process of breaking up of a moiety into its constituent atoms, molecules and ions.