The limiting molar conductivities λ∘ for NaCl,KBr and KCl are 126, 152 and 150 S cm2 mol−1respectively. The λ∘ for NaBr is
(126 scm2)∧∘NaCl=∧∘Na++∧∘Cl− .......(1)
(152 scm2)∧∘KBr=∧∘K++∧∘Br− .......(2)
(150 scm2)∧∘KCl=∧∘K++∧∘Cl− .......(3)
By equation (1)+(2)−(3)
∵ ∧∘NaBr=∧∘Na++∧∘Br−=126+152−150=128 Scm2mol−1