TO DETERMINE THE CELL CONSTANT OF THE GEVEN CONDUCTIVITY CELL

 

APPARATUS REQUIRED

• Conductivity bridge with conductivity cell

• volumetric flask

•  pipette

CHEMICALS REQUIRED

• 0.1N Kcl 

• 0.01NKcl

• conductivity water

PRINCIPLE

A conductivity cell consists of I plates (paralel) platinum electrodes which are fixed in a The electrodes are separated at a fixed area of cross section glass tubes. fix distance i with 'a' and the ratio a of the cell is constant which is called cell constant 

cell constant (L) = l/a

we have the specific conductance of an electrolyte solution 

k= a× l/a [λ = observe conductance]

cell constant (l/a)=specific conductance (k) ÷ observed conductance

In practice the specific conductances of kcl solution at different concentration are known and to find the cell constant, the conductance of a known concentration of kcl solution is determined.

PROCEDURE

The conductometer was first calibrated as follows:.

The cell was first rinsed with distilled water and immersed in conductivity standard solution. The cell was shaked gently to avoid air bubbles & CAL was pressed. Then ↩️was pressed when ☺️ apparace. Then to measure the conductance of given be solutions, the cell was dipped in first the conductivity water & then kcl of 0.01 N concentration and for 0.1N kcl too, same process was done and the results were noted.

OBSERVATION

CALCULATION

cell constant (L) = 1.386×10-3 ÷ 1.296×10-3

                              = 1.06

from 0.1 N kcl, cell constant) (L) = 1.264x10-2 ÷ 1.004×10-2 =1.26

RESULT

Hence the mean value of coll constant of given conductivity cell was found to be 1.16

CONCLUSION

The cell constant of given conductivity cell can be determined.