1. Polarization of Water Molecules: The polar water molecules, each consisting of a positively charged hydrogen atom and a negatively charged oxygen atom, surround the ionic compound. The positive end of the water molecules is attracted to the negative ions (Cl-), while the negative end of the water molecules is attracted to the positive ions (K+).
2. Formation of Hydrated Ions: The water molecules form a layer around each ion, known as a hydration shell. The hydrated ions are surrounded by water molecules with their oppositely charged ends facing inwards, creating a stable configuration that prevents the ions from recombining. This process is driven by the electrostatic interactions between the ions and the polar water molecules.
3. Breaking of Ionic Bonds: The strong electrostatic forces holding the positive and negative ions together in the crystal lattice are overcome by the polar nature of water molecules. The water molecules weaken these ionic bonds, causing the ions to separate and disperse into the solution.
4. Dissociation: As a result of the hydration and breaking of ionic bonds, the ionic compound dissociates into its constituent ions. The positive ions (K+) and negative ions (Cl-) become surrounded by their respective hydration shells and move freely in the water.
5. Solvation: The hydrated ions are then solvated by water molecules, meaning they are surrounded and stabilized by water molecules. The water molecules form a dynamic solvation shell around the ions, constantly exchanging with other water molecules in a continuous process.
The dissolution of KCl in water can be represented by the following chemical equation:
```
KCl (s) + H2O (l) → K+ (aq) + Cl- (aq)
```
In summary, the dissolution of ionic substances in water involves the polarization of water molecules, the formation of hydrated ions, the breaking of ionic bonds, dissociation into individual ions, and solvation by water molecules. These processes result in the formation of a homogeneous solution containing dispersed hydrated ions.