Dissociation and dissolution are distinct processes that describe how a solute interacts with a solvent, most commonly water.
Dissolution vs. Dissociation: Key Differences
| Feature | Dissolution | Dissociation |
|---|---|---|
| Definition | The process of a solute dissolving. | The separation of ions when an ionic compound dissolves. |
| Change Type | Physical change | Chemical change |
| Bonds | No chemical bonds are broken. | Chemical bonds are broken. |
| Solute Type | Can occur with both ionic and nonionic compounds. | Primarily occurs with ionic compounds. |
| Example | Sugar dissolving in water. | NaCl (table salt) dissolving in water. |
In-Depth Explanation
Dissolution: A Physical Change
Dissolution is the process where a solute disperses evenly throughout a solvent, forming a solution. This is a physical change because the chemical identity of the solute remains the same. The solute particles (molecules or ions) are surrounded by solvent molecules.
- Example: When sugar (a nonionic compound) dissolves in water, the sugar molecules are surrounded by water molecules, but the sugar molecules themselves do not break apart into ions.
Dissociation: A Chemical Change
Dissociation, according to Flexi Says, is the separation of ions that occurs when a solid ionic compound dissolves. This is a chemical change because the ionic bonds holding the compound together are broken. Consequently, dissociation does not occur with nonionic compounds.
- Example: When NaCl (sodium chloride) dissolves in water, it dissociates into Na+ (sodium ions) and Cl- (chloride ions). These ions are then surrounded by water molecules. The ionic bond between Na and Cl is broken in the process.
Summarizing the Difference
In simple terms:
- Dissolution is the general process of something dissolving.
- Dissociation is a specific type of dissolution where an ionic compound breaks apart into its constituent ions.
