Question

Explain how the dissolving of an ionic solute in water represents an equilibrium process.

Short answer

The dissolving of an ionic solute in water represents an equilibrium process because it involves simultaneous forward and reverse reactions occurring at constant rates. In this process, the ionic solute dissociates into its constituent ions due to the interactions with water molecules, while the reverse reaction causes the hydrated ions to collide and re-form the ionic solute as solid crystals. When the rate of the forward and reverse reactions becomes equal, the system reaches a state of equilibrium, with constant concentrations of solute and ions in the solution.

Step-by-step solution

Understand Equilibrium Process

An equilibrium process can be defined as a state in which the forward and reverse reactions occur simultaneously and at the same rate. In such a state, the concentrations of reactants and products remain constant, and there are no external changes in the system.

Identify the Ionic Solute and Interactions with Water

An ionic solute is a compound that dissociates into positive (cations) and negative (anions) ions when dissolved in water. Water molecules have the capability to dissolve many ionic compounds because of their dipole nature, having a positive end (hydrogen atoms) and negative end (oxygen atom). When an ionic solute is introduced into water, the positive end of water molecules interacts with anions, and the negative end of water molecules interacts with cations. These interactions help to overcome the electrostatic forces between the ions and separate them from the crystal lattice, causing the solute to dissolve.

Explain the Forward and Reverse Reactions

In the forward reaction, the ionic solute dissociates into its constituent ions, and the water molecules cluster around these ions through the process of hydration. In the reverse reaction, the hydrated ions collide with each other and form the ionic solute again, which leaves the aqueous solution and forms solid crystals.

Describe the Establishment of Equilibrium

As the ionic solute dissolves in water, the forward reaction starts, and the concentration of the constituent ions increases in the solution. Simultaneously, the rate of the reverse reaction also increases due to the presence of ions in the solution. At some point, the rate of the forward reaction (dissolving of solute) will be equal to the rate of the reverse reaction (precipitation of solute). When this occurs, the system is in a state of equilibrium, and the concentrations of solute and ions remain constant. In conclusion, the dissolving of an ionic solute in water represents an equilibrium process as it involves both forward and reverse reactions occurring simultaneously and at constant rates, with no change in the concentrations of reactants and products in the system.