Question

which of the following illustrations would not increase the rate of dissolution of solid solutes in aqueous solutions? 1 2 3 4 a 4 only b 1 and 2 only c 1 2 and 3 only

Explanation:

1. Agitation (stirring): Increases the rate of dissolution as it helps to distribute the solute particles and brings fresh solvent into contact with the solute. So, illustration 1 (stirring) increases the dissolution rate.
2. Surface - area increase (crushing): Breaking the solid into smaller pieces (crushing) increases the surface - area. A larger surface - area means more contact between the solute and the solvent, increasing the dissolution rate. So, illustration 2 (crushing) increases the dissolution rate.
3. Temperature increase: For most solid solutes in aqueous solutions, an increase in temperature increases the kinetic energy of both solute and solvent particles. This leads to more frequent and energetic collisions, increasing the dissolution rate. So, illustration 3 (heating) increases the dissolution rate.
4. Adding more solvent: Adding more solvent (illustration 4) does not increase the rate of dissolution. The rate of dissolution is related to how quickly the solute dissolves, and adding more solvent only allows more solute to dissolve (increases the solubility limit in terms of the total amount of solute that can be dissolved), but it does not make the solute dissolve faster.

Answer:

A. 4 only