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State Kohlrausch law of independent migr...

State Kohlrausch law of independent migration of ions. Why does the conductivity of a solution decrease with dilution ?

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Kohlrausch law of independent migration of ions states that limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of anion and cation of the electrolyte.
If `Lambda_(Na^(+))^(@)` and `Lambda_(Cl^(-))^(@)` are the limiting molar conductivities for sodium and chloride ions respectively, then limiting molar conductivity for sodium chloride is given by the equation :
`Lambda_(m)^(@) (NaCl) = lambda_(Na^(+))^(@) + lambda_(Cl^(-))^(@)`
Conductivity of a solution decreases with dilution because the number of ions per unit volume of the solution decreases.
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(a) State Kohlrausch law of independent migration of ions. Write an expression for the molar conductivity of acetic acid at infinite dilution according to Kohlrausch law. (b) Calculate Lambda_(m)^(@) , for acetic acid. Given that Lambda_(m)^(@) (HCl) = 426 S cm^(2) mol^(-1) Lambda_(m)^(@) (NaCl) = 126 S cm^(2) mol^(-1) Lambda_(m)^(@) (CH_(3)COONa) = 91 S cm^(2) mol^(-1)

State Kohlrausch law of independent migration of ions. Write an expression for the molar conductivity of acetic acid at infinite dilution according to Kohlrausch law. {:((b),"Calculate",:,wedge^(@)m" for acetic acid."),(,"Given that",:,wedge^(@)m(HCl)=426 " S " "cm"^(2)mol^(-1)),(,,,wedge^(@) m(NaCl)=126 " S " cm^(2) mol^(-1)),(,,,wedge^(@) m(CH_(3)COONa)=91 " S " cm^(2)mol^(-1)):}

Read the given passage and answer the questions number that follow : Weak electrolytes like acetic acid have lower degree of dissociation at higher concentrations and hence for such electrolytes, the change in Lambda_(m) with dilution is due to increase in the degree of dissociation and consequently the number of ions in total volume of solution that contains one mol of electrolyte. In such cases Lambda_(m) increases steeply on dilution, especially near lower concentrations. Therefore, Lambda_(m) cannot be obtained by extrapolation of Lambda_(m) to zero concentration. At infinite dilution (i.e., concentration c to zero) electrolyte dissociates completely ( alpha = 1), but at such low concentration the conductivity of the solution is so low that it cannot be measured accurately. Therefore, Lambda_(m)^(@) for weak electrolytes is obtained by using Kohlrausch law of independence migration of ions. Why does the change in Am take place on dilution in case of weak electrolytes ?

Kohlrausch Law Of Independent Migration Of Ions|Questions|Summary

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