The correct option is D (Λ0m)NaBr−(Λ0m)NaI=(Λ0m)KBr−(Λ0m)NaBr
Kohlrausch law of independent migration of ions:
Λ0m=λ0++λ0−
λ0+→Limiting molar conductivities of cation
λ0−→Limiting molar conductivities of anion
In general,
Λ0m=v+λ0++v−λ0−
v+ and v− are the number of cations and anions after dissociation of an electrolyte.
In option (3),
(Λ0m)NaBr−(Λ0m)NaI=(Λ0m)Br+−(Λ0m)I−
(Λ0m)KBr−(Λ0m)NaBr=(Λ0m)K+−(Λ0m)Na+
Thus,
(Λ0m)NaBr−(Λ0m)NaI≠(Λ0m)KBr−(Λ0m)NaBr
Hence, option (c) is correct.