Among Co3+, Ti2+, V2+ and Cr2+ ions, one if used as a reagent cannot liberate H2 from dilute mineral acid solution, its spin-only magnetic moment in gaseous state is ___________ B.M. (Nearest integer)
Answer (integer)
5
Solution
$\mathrm{Co}^{3+}$ will not liberate $\mathrm{H}_{2}$ gas an reaction with dilute acid
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$\mathrm{E}_{\mathrm{Co}^{3+}/\mathrm{Co}^{2+}}^{\mathrm{O}}=+1.97$
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And $\mathrm{Co}^{3+}$ has electronic configuration $=[\operatorname{Ar}] 3 d^{6}$
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$\therefore 4$ unpaired $\mathrm{e}^{-}$ are present in it
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$\therefore$ Spin-only magnetic moment $=\sqrt{4(4+2)} =4.92 \approx 5$
About this question
Subject: Chemistry · Chapter: d and f Block Elements · Topic: Properties of Transition Metals
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