Which of the following has the highest molar conductivty?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → potassium hexacyanoferrate(II)
Molar conductivity (Λm\Lambda_mΛm) depends on the number of ions in solution and their mobility:
- K₄[Fe(CN)₆] → 4 K⁺ + [Fe(CN)₆]⁴⁻ → total 5 ions
- [Cr(H₂O)₆]Cl₂ → [Cr(H₂O)₆]²⁺ + 2 Cl⁻ → total 3 ions
- [Co(NH₃)₄Cl₂]Cl → [Co(NH₃)₄Cl₂]⁺ + Cl⁻ → total 2 ions
- K₂[Ni(CN)₄] → 2 K⁺ + [Ni(CN)₄]²⁻ → total 3 ions
- More ions → higher molar conductivity.
- Therefore, K₄[Fe(CN)₆] produces the most ions and has the highest molar conductivity.