The molar conductivities at infinite dilution for NaI, CH₃COONa and ( CH₃COO) ₂ Mg are 12.69, 9.10 and 18.78 S m² mol⁻¹. What is Λ _°m for MgI₂  ? 

  Molar conductivity for MgI₂ can be calculated as follow:

                 Λ^∞ (CH₃COO)₂Mg =  18.78     

                  Λ^∞ NaI  =  12.69 

                   Λ^∞CH₃COONa  = 9.10

                   Λ^∞MgI₂ =  x

Λ^∞ MgI₂ =  Λ^∞ (CH₃COO)₂Mg + Λ^∞ NaI  -  Λ^∞ CH₃COONa

  x = 18.78  + 12.69  - 9.10   

  22.37  =  x

  There for Λ °m for MgI₂ is 22.37 S m² mol⁻¹.