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The molar conductance of NaCl varies with the concentration as shown in the following table. And all values follows the equation lambda_m^C=lambda_m^oo-bsqrtC Where lambda_m^C=Molar specific conductance lambda_m^oo=Molar specific conductance at infinite direction C=Molar concentration {:("Molar Concentration of NaCl","Molar Conductance inohm"^(-1)cm^(2)"mole"^(1)),(4xx10^(-4),107),(9xx10^(-4),97),(16xx10^(-4),87):} When a certain conductivity cell (C ) was filled with 25xx10^(-4) (M) NaCl solution.The resistance of the cell was found to be 1000 ohm.At infinite dilution, conductance of Cl^(-) and SO_(4)^(-2) are 800 "ohm"^(-1) cm^(2)"mole"^(-1) and 160 "ohm"^(-1) cm^(2)"mole"^(-1) respectively. What is the cell constant of the conductivity cell ( C) ? |
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Answer» `0.385 CM^(-1)` `lambda_m=lambda_m^oo-bsqrtC` `lambda_m=127-10^3(25xx10^(-4))^(1//2)` `lambda_m=127-10^(3)xx5xx10^(-2)` `lambda_m=77` But `lambda_m=(Kxx1000)/M " " K=(l/a)xx1/R` `lambda_m=(l/a)xx1/Rxx1000/M` `lambda_m`=[Cell CONSTANT]`xx1000/(RxxM)` `implies `77=[Cell constant]`xx1000/(1000xx25xx10^(-4))` Cell constant `=77xx25xx10^(-4)=0.1925 cm^(-1)` |
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