Chapter 15, Problem 9STP

Interpretation Introduction

Interpretation: To explain the settlement of colloidal and solution particles.

Concept Introduction: A solution is considered a homogenous mixture that is made by combining the solute and the solvent. When a homogenous solution is left undisturbed, the particles will not settle down because the solute will completely dissolve in the solvent. When heterogeneous solutions such as sand and water are considered, the solute particles will settle down when left undisturbed. Colloidal solutions are those which contain a mixture of particles of a substance.

Answer to Problem 9STP

Both assertion and reason are incorrect.

Explanation of Solution

Colloidal particles do not settle down due to Brownian movement. Brownian movement is the random movement of molecules suspended in the medium. This medium can be liquid or gas and due to the collision between the molecules, random movement will take place which will not allow the particles to settle to the bottom of the colloidal solution. Whereas in a heterogenous solution there is no such movement, therefore, they settle at the bottom of the solution.

Conclusion

The settlement of the particles depends upon the movement of the particles. If there is a movement or collision between the molecules, it will be difficult for those particles to settle down to the bottom of the solution.