When soluble ionic compounds dissolve in water, they dissociate into their constituent ions. This process occurs because the polar water molecules interact with the charged ions of the compound, pulling them apart and allowing them to disperse throughout the solution.
To describe this process, we can take a common ionic compound, like sodium chloride (NaCl), as an example:
-
Dissociation of Sodium Chloride (NaCl):
- Sodium chloride is made up of sodium ions (Na⁺) and chloride ions (Cl⁻). When NaCl is added to water, the following dissociation occurs: \[ \text{NaCl (s)} \rightarrow \text{Na}^+ (aq) + \text{Cl}^- (aq) \]
- Here, (s) indicates that NaCl is in solid form, while (aq) indicates that the ions are in an aqueous solution.
-
General Process:
- This dissociation process can be generalized for other soluble ionic compounds: \[ \text{AB (s)} \rightarrow \text{A}^+ (aq) + \text{B}^- (aq) \]
- In this notation, A and B represent the cation and anion, respectively.
-
Factors Influencing Solubility:
- The solubility of ionic compounds in water is influenced by factors such as:
- The nature of the ions (size and charge).
- The temperature of the water.
- The presence of other ions in the solution (which may lead to precipitation).
- The solubility of ionic compounds in water is influenced by factors such as:
-
Examples of Soluble Ionic Compounds:
- Other examples include:
- Potassium nitrate (KNO₃): \[ \text{KNO}_3 (s) \rightarrow \text{K}^+ (aq) + \text{NO}_3^- (aq) \]
- Calcium chloride (CaCl₂): \[ \text{CaCl}_2 (s) \rightarrow \text{Ca}^{2+} (aq) + 2 \text{Cl}^- (aq) \]
- Sodium bicarbonate (NaHCO₃): \[ \text{NaHCO}_3 (s) \rightarrow \text{Na}^+ (aq) + \text{HCO}_3^- (aq) \]
- Other examples include:
This process of dissociation into ions is critical for various chemical reactions, biological processes, and solutions' electrical conductivity.