Chapter 15, Problem 7STP

Interpretation Introduction

Interpretation : To compare the conductivity of the given solution.

Concept Introduction: Conductivity is defined as the ability of an electrolyte or a solute to conduct electricity. Not all the solutions need to conduct electricity as all the solutions are not electrolytes. Therefore, only the solutions which can dissociate can participate in conduction.

Answer to Problem 7STP

  ${\text{AlCl}}_{\text{3}}$ will contain four ions and $\text{KCl}$ will have only two ions.

Explanation of Solution

The dissociation of ${\text{AlCl}}_{\text{3}}$ will produce four ions and the dissociation will be as follows:

  ${\text{AlCl}}_{\text{3}}\rightleftharpoons {\text{Al}}^{\text{3+}}{\text{+3Cl}}^{\text{-}}$

Similarly, when the dissociation of $\text{KCl}$ takes place it will produce only two ions and the dissociation will be as follows:

  $\text{KCl}\rightleftharpoons {\text{K}}^{\text{+}}{\text{+Cl}}^{\text{-}}$

Since the ions are doubled in case of ${\text{AlCl}}_{\text{3}}$ , therefore, the conductivity of ${\text{AlCl}}_{\text{3}}$ is twice as that of the $\text{KCl}$

Conclusion

When there are a greater number of free electrons, then the conductivity will be good. The conductivity is purely based on the number of ions that are present in the solution. When there are no ions in the solution, the conductivity will be nil.