Question

The conductivity of strong electrolytes:
A.increases on dilution slightly
B.does not change on dilution
C.decreases on dilution
D.depends on density of electrolyte itself

Answer 1

Hint:Conductivity of an electrolytic solution at a given temperature and concentration is the conductance of the unit volume of the solution. It is the conductance when the solution is kept between two platinum electrodes with a unit area of cross-section which is kept at a distance of unit length. Strong electrolytes are that electrolyte that completely or almost completely disassociate in a solution to form ions thus making the solution a good conductor. Whereas the process of increasing the solvent in the solution to increasing the volume with the amount of solute being the same is called dilution.

Complete step by step answer:
-The conductivity of the electrolytic solution is a measure of the ability to conduct electricity. It has the SI unit of Siemens $(S)$ and is represented by $\kappa $ (kappa). It has the SI unit of $S{m^{ - 1}}$
-Conductivity depends on the nature of the material, temperature, and pressure.
-Conductivity changes with the concentration of the electrolyte.
-Conductivity always decreases with a decrease in concentration both, for weak and strong electrolytes.
This is because the number of ions per unit volume that carries the current in the solution decreases on dilution.
-The conductivity of the solution for any given concentration is the conductance of one unit volume of solution kept between two platinum electrodes with a unit area of the cross-section at a distance of unit length. This can be depicted from the equation below.
$G = \dfrac{{\kappa A}}{l} = \kappa $ (both $A$ and $l$ are unity in their appropriate units)
-Upon dilution, the amount of ions in the solution remains the same while the volume increases thus decreasing the number of ions per volume thus decreasing the conductivity of the electrolyte.
So the correct answer is option (C).


Note:
-Conductivity is also known as specific conductance.
-Conductivity $(\kappa )$ is the inverse of resistivity $(\rho )$
-The conductivity of the electrolyte differs due to the change in the size of the ions in which they dissociate, the concentration of the ions, or the ease with which the ions move under a potential gradient.