Final answer:
The molar conductivity (λμ) of an electrolyte is related to the sum of the molar ionic conductivities of the cation and anion, with coefficients for each ion based on the stoichiometry of the dissociation in solution.
Step-by-step explanation:
The relation between molar conductivity and molar ionic conductivities for the given electrolytes is derived from the dissociation of each into its constituent ions in solution. Molar conductivity, which is often denoted by the symbol λμ, is the conductivity of an electrolyte solution divided by the molar concentration of the electrolyte. It is related to the ionic conductivities of the cation and the anion that form when an electrolyte dissociates in aqueous solution.
For the dissociation of the given electrolytes:
- KBr dissociates into K+ and Br− ions.
- Na2SO4 dissociates into 2Na+ and SO42− ions.
- AlCl3 dissociates into Al3+ and 3Cl− ions.
The molar conductivity λμ of each electrolyte is the sum of the molar ionic conductivities of its constituent ions:
- For KBr,
λμ(KBr) = λμ(K+) + λμ(Br−) - For Na2SO4,
λμ(Na2SO4) = 2×λμ(Na+) + λμ(SO42−) - For AlCl3,
λμ(AlCl3) = λμ(Al3+) + 3×λμ(Cl−)
These expressions assume that all species are fully dissociated in solution, which is a valid approximation for strong electrolytes in dilute solutions.
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