Question

The cell constant of a conductivity cell:
A. Changes with change of electrolyte
B. Changed with change of concentration of electrolyte
C. Changed with change of temperature of electrolyte
D. remains constant for a cell

Answer 1

Hint: The cell constant is denoted by 'k' and has a unit of per metre or per centimetre. Any solution with a known conductivity we can determine the cell constant. Conductivity is an ability of any substance to allow current through it.

Complete step by step solution:
-The formula of cell constant (k) is the ratio of the distance between two electrodes and the area of the electrodes in centimetre per square.
-When two electrodes are placed close to each other, then the conductivity of the electrodes is high.
-Whereas when the electrodes are kept far from each other then the ability to conduct becomes low.
-So, option D. is the correct answer.
-As we can see, the formula of the cell constant depends only on the distance of the electrodes and the area of each electrode.
-It does not matter if we change the electrode.
-So, option A. is an incorrect answer.
 -If we change the concentration of electrolyte, it does not affect the cell constant because the cell constant depends only on the area and distance between the electrodes.
-So, we can change the concentration of the electrolyte but by keeping it in the right distance.
Hence, option B. is also an incorrect answer.
-It was observed that if we change the temperature of the solution the value of cell constant (k) doesn't change.
-Because the distance between the electrode and area of the electrode was kept the same.
-So, option C. is also an incorrect answer.

So, the correct answer is “Option D”.

Note: The value of cell constant (k) is less than one when the conductivity of an electrode is high. Whereas if the conductivity of an electrode is low then the value of conductivity can raise up to 1.