KX refers to an unknown compound represented by X that dissociates into its constituent ions when dissolved in water. The "K" represents potassium (K+).
Related terms
Ionization: The process by which compounds break down into their constituent ions when dissolved in water.
Dissociation: Similar to ionization, this refers specifically to the separation of molecules into their constituent ions.
Solubility: The ability for substances to dissolve in water or other solvents.