Verified Solution • 2025–26 Session moderate

QJEEM20Cha6ce: JEE Main 2020 Chemistry - Class 12 JEEM20Cha6ce Solution: Among the statements(a)-(d) the incorrect ones are : (a)…

Among the statements(a)-(d) the incorrect ones are :
(a) Octahedral CO(III) complexes with strong fields ligands have very high magnetic moments.
(b) When Δ0 < P, the d-electron configuration of Co(III) in an octahedral complex is teg4eg2
(c) Wavelength of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3-
(d) If the Δ0 for an octahedral complex of CO(III) is 18,000 cm-1, the Δt for its tetrahedral complex with the same ligand be 16,000 cm-1

Multiple Choice Options

  • A (a) and (b) only
  • B (b) and (c) only
  • C (c) and (d) only
  • D (a) and (d) only

Step-by-Step Verified Solution

(a) Co3+ with strong field complex forms low magnetic moment complex.

(b) If Δ0 < P configuration of Co3+ will be teg4eg2.

(c) Splitting power of ethylenediamine (en) is greater than fluoride (F–) ligand therefore more energy absorbed by [Co(en)3]3+ as compared to [CoF6]3–.

So wave length of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3–

(d) Δt=49Δ0 = 49×18000 = 8000 cm-1

∴ Statement (a) and (d) are incorrect.

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