Question

At the state of dynamic equilibrium, for solute + solvent gives solution.

• A. Rate of dissolution = Rate of unsaturation.
• B. Rate of dissolution = Rate of crystallization
• C. Rate of dissolution = Rate of saturation
• D. Rate of crystallization = Rate of saturation.

Hint:

Key Exam Tip:
Dynamic equilibrium in a saturated solution is a state where opposing processes occur at equal rates. For dissolution, these processes are:
• Dissolution: Solute particles break away from the solid and enter the solution.
• Crystallization: Dissolved solute particles aggregate and return to the solid state. When these rates are equal, the solution is saturated, and no net change is observed.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
When a solid solute is added to a solvent, two opposing physical processes occur:
1. Dissolution: Solute particles leave the solid phase and enter the liquid phase.
2. Crystallization: Dissolved solute particles collide with the solid surface and re-attach to the solid phase.
Step 2: Detailed Explanation:
Initially, the rate of dissolution is high. As more solute dissolves, the concentration increases, and the rate of crystallization also increases.
Eventually, a state is reached where the number of particles entering the solution equals the number of particles leaving it.
\[ \text{Solute} + \text{Solvent} \rightleftharpoons \text{Solution} \]
At this point, the concentration of the solution becomes constant at a given temperature. This is known as a saturated solution.
Step 3: Final Answer:
Dynamic equilibrium is defined by the equality of the rates of the forward and backward processes. Therefore, Rate of dissolution \( = \) Rate of crystallization.