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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. If the cell ( C) is filled with 5xx10^(-3) (N)Na_2SO_4 the observed resistance was 400 ohm. What is the molar conductance of Na_2SO_4 ? |
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Answer» `19.25 ohm^(-1) cm^(2) "mole"^(-1)` `K=(l/a)xx1/R=0.1925/400=4.81xx10^(-4) ohm^(-1)cm^(-1)` `lambda_m=(Kxx1000)/M=(4.81xx10^(-4)xx1000)/(5/2xx10^(-3))` `lambda_m(Na_2SO_4)=192.4 ohm^(-1) cm^2 "mole"^(-1)` |
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