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InterviewSolution
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What is conductivity cell constant ? Give a note on conductivity cell constant (""^(*)G). |
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Answer» SOLUTION :* The quantity `((l)/(A))` is called cell constant denoted by the symbol `G^(**)(G^(**)=((l)/(A)))` Where, l=distance between two ELECTRODES of cell , A=cross sectional area * If we know land A. Measurement of l and A is not only inconvenient but also unreliable. * (A) Measurement of cell resistance : * Only one type of conductivity cell is used during the routine experiments. * The cell constant is usually determined by measuring the resistance of the cell containing by measuring the resistance of the cell containing solution whose conductivity is already known. * For this purpose, we generally use KCl solutions whose conductivity is known accurately at various concentrations and at different temperatures.  * 0.1 M KCl solution is to be filled in conductivity cell and then resistance of cell can be MEASURED, By this was cell constant can be measured. * (B) Procedure: By filling the concentration cell with known concentration of KCl and then it is attached with Wheatstone bridge by attaching with AC current source. * (C) Calculation of cell constant `G^(**):(G^(**)=((l)/(A))=Rkappa)` Where, R=resistance of KCl solution experimental VALUE. `kappa`=conductivity of KCl obtained from the table. `G^(**)`=cell constant, whose calculation can be done at laboratory temperature. Note: by this way cell constant can be measured and it is used to measure the conductivity of any solution. |
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