Which one of the following ligand produces weakest field?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → SCN−
Ligands arranged in order of increasing field strength form the spectrochemical series. The four given ligands appear in it as SCN− < S2− < F− < OH−.
Of the four given ligands, SCN− (bonded through S) comes first, so it produces the weakest field.
Why the other options are incorrect
Option (2) S2− — Incorrect. It lies after \( \ce{SCN^{-}} \) and \( \ce{Cl^{-}} \) in the series, so it gives a stronger field than \( \ce{SCN^{-}} \).
Option (3) F− — Incorrect. It lies after \( \ce{S^{2-}} \), a stronger field than \( \ce{SCN^{-}} \).
Option (4) OH− — Incorrect. It is the strongest of the four given ligands.
NCERT (2026-27 edition):
Crystal Field Theory – …
