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
Solution
(a) Co<sup>3+</sup> with strong field complex forms low
magnetic moment complex.
<br><br>(b) If $\Delta$<sub>0</sub> < P configuration of Co<sup>3+</sup> will be $t_{eg}^4e_g^2$.
<br><br>(c) Splitting power of ethylenediamine (en) is
greater than fluoride (F<sup>–</sup>) ligand therefore more
energy absorbed by [Co(en)<sub>3</sub>]<sup>3+</sup> as compared to
[CoF<sub>6</sub>]<sup>3–</sup>.
<br><br>So wave length of light absorbed by [Co(en)<sub>3</sub>]<sup>3+</sup>
is lower than that of [CoF<sub>6</sub>]<sup>3–</sup>
<br><br>(d) ${\Delta _t} = {4 \over 9}{\Delta _0}$ = ${4 \over 9} \times 18000$ = 8000 cm<sup>-1</sup>
<br><br>$\therefore$ Statement (a) and (d) are incorrect.
About this question
Subject: Chemistry · Chapter: Coordination Compounds · Topic: Ligands and Coordination Number
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