Question

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

Answer 1

Cell constant is the ratio of distance between the electrodes and area of cross-section of electrodes in a cell.A cell constant has units of 1/cm (per centimeter), where the number refers to the ratio of the distance between the electrode plates to the surface area of the plate.

Complete answer:
-The formula to find out cell constant is,
Cell constant, $K = \dfrac{l}{A}$
Where $l$ is the distance between the electrodes and $A$ is the area of cross-section of electrodes in a cell.
-From this equation, we can say that cell constant has no relation with the nature of electrolyte used. Hence cell constant will not change with change in electrolyte. So, option A is wrong.
-Also, from the equation we can say that change in temperature or concentration of electrolyte has no effect on cell constant. Value of cell constant is independent of electrolyte. Hence option C and D are also wrong.
-For a particular cell, distance between electrodes and cross-section of electrodes remains constant. -Hence the ratio of distance between electrodes and cross-section of electrodes also remains constant for a particular cell. Thus cell constant remains constant for a cell.
Hence option B is correct.

Additional information-
The distance between electrodes is usually expressed in cm. Also cross-section of electrodes is expressed in $c{m^2}$. Hence the unit of cell constant will be $c{m^{ - 1}}$.
In order to find the amount of current that flows through a specific amount of liquid, the volume between the electrodes must be constant. This volume is defined as the cell constant.

Note:
Cell constant remains constant for a particular cell. Cell constant is also represented as ${G^*}$.There are two types of electrochemical cells: galvanic, also called Voltaic, and electrolytic. Galvanic cells derive their energy from spontaneous redox reactions, while electrolytic cells involve non-spontaneous reactions and thus require an external electron source like a DC battery or an AC power source.