Which of the following cannot be used as standard solution for determination of cell constant of…
Which of the following cannot be used as standard solution for determination of cell constant of conductivity cell?
1 M KCl
0.1 M KCl
$0.01 \mathrm{M} \mathrm{KCl}$
Saturated KCl
Solution
Saturated KCl Solution :
A saturated solution of KCl is not typically used as a standard solution for conductivity calibration. The reason is that a saturated KCl solution may have variable composition due to temperature changes, partial crystallization, and difficulty in ensuring a uniform, reproducible concentration. Thus, it does not have a precisely known or easily reproducible conductivity value as the other standard concentrations do.
Conclusion :
Out of the given options, the saturated KCl solution (Option D) is not suitable for use as a standard solution in determining the cell constant because its concentration and thus its conductivity are not stable or easily reproducible.