Which of the following would increase the rate of dissolution of a solid in a solution? 1) Cool the solid and the solution 2) Cool only the solid 3) Dry up the solvent 4) Stir the solid and solution
The Correct Answer and Explanation is :
The correct answer is 4) Stir the solid and solution.
Explanation:
The rate of dissolution refers to how quickly a solute dissolves in a solvent to form a solution. Several factors affect the rate of dissolution, including temperature, surface area of the solute, agitation (stirring), and the nature of the solvent.
- Cool the solid and the solution: Cooling both the solid and the solution typically decreases the rate of dissolution. This is because dissolving is often an exothermic process, meaning it releases heat. Lowering the temperature reduces the solubility of many solutes in solvents and slows down the process of dissolution. Cold temperatures reduce the kinetic energy of the molecules involved, making it harder for the solute molecules to break free from the solid and interact with the solvent molecules.
- Cool only the solid: Cooling only the solid also reduces the dissolution rate. When the solid is cooled, the solute particles have less kinetic energy and move less freely. As a result, they have a harder time breaking away from the solid and interacting with the solvent, thus slowing down the rate of dissolution.
- Dry up the solvent: Removing solvent (drying up the solvent) would decrease the concentration of the solvent available to dissolve the solute. With less solvent, there is less capacity to dissolve the solute, and this would reduce the rate of dissolution or stop it altogether.
- Stir the solid and solution: Stirring or agitating the solution increases the rate of dissolution. Stirring helps distribute the solute particles throughout the solvent more evenly, allowing fresh solvent to come into contact with the solute particles. This increases the frequency of collisions between the solute and solvent molecules, which speeds up the process of dissolution. Stirring also helps remove any solute particles that have already dissolved, making more surface area of the solute available for interaction with the solvent.
In summary, stirring (agitation) enhances the dissolution process by facilitating greater interaction between the solute and solvent molecules, thus increasing the rate of dissolution.