JEE MAIN - Chemistry (2020 - 7th January Evening Slot - No. 2)
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 $$\Delta $$0 < P, the d-electron configuration of Co(III) in an octahedral complex is $$t_{eg}^4e_g^2$$
(c) Wavelength of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3-
(d) If the $$\Delta $$0 for an octahedral complex of CO(III) is 18,000 cm-1, the $$\Delta $$t for its tetrahedral complex with the same ligand be 16,000 cm-1
(a) Octahedral CO(III) complexes with strong fields ligands have very high magnetic moments.
(b) When $$\Delta $$0 < P, the d-electron configuration of Co(III) in an octahedral complex is $$t_{eg}^4e_g^2$$
(c) Wavelength of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3-
(d) If the $$\Delta $$0 for an octahedral complex of CO(III) is 18,000 cm-1, the $$\Delta $$t for its tetrahedral complex with the same ligand be 16,000 cm-1
(a) and (b) only
(b) and (c) only
(c) and (d) only
(a) and (d) only
Explanation
(a) Co3+ with strong field complex forms low
magnetic moment complex.
(b) If $$\Delta $$0 < P configuration of Co3+ will be $$t_{eg}^4e_g^2$$.
(c) Splitting power of ethylenediamine (en) is greater than fluoride (Fā) ligand therefore more energy absorbed by [Co(en)3]3+ as compared to [CoF6]3ā.
So wave length of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3ā
(d) $${\Delta _t} = {4 \over 9}{\Delta _0}$$ = $${4 \over 9} \times 18000$$ = 8000 cm-1
$$ \therefore $$ Statement (a) and (d) are incorrect.
(b) If $$\Delta $$0 < P configuration of Co3+ will be $$t_{eg}^4e_g^2$$.
(c) Splitting power of ethylenediamine (en) is greater than fluoride (Fā) ligand therefore more energy absorbed by [Co(en)3]3+ as compared to [CoF6]3ā.
So wave length of light absorbed by [Co(en)3]3+ is lower than that of [CoF6]3ā
(d) $${\Delta _t} = {4 \over 9}{\Delta _0}$$ = $${4 \over 9} \times 18000$$ = 8000 cm-1
$$ \therefore $$ Statement (a) and (d) are incorrect.
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