The Co(III) aqua complex slowly undergoes redox decomposition to give the Co(II) aqua complex and oxygen, but in presence of 'en', Co (II) is slowly oxidised to [ Co ( en ) 3 ] 3 + by aeri

Question

The Co(III) aqua complex slowly undergoes redox decomposition to give the Co(II) aqua complex and oxygen, but in presence of 'en', Co (II) is slowly oxidised to [ Co ( en ) 3 ​ ] 3 + by aerial oxygen. Select correct statement(s) :

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The correct statements are (C) and (D) based on the following principles:

Redox decomposition converts $[C o (H_{2} O)_{6}]^{3 +}$ into $[C o (H_{2} O)_{6}]^{2 +}$ , where a decrease in oxidation state ( $+ 3$ to $+ 2$ ) decreases the crystal field splitting energy ( $Δ_{o}$ ).

Aerial oxidation converts the $C o (II)$ ethylenediamine complex into $[C o (e n)_{3}]^{3 +}$ , where an increase in oxidation state ( $+ 2$ to $+ 3$ ) and a stronger field ligand ('en' > $H_{2} O$ ) increases the $Δ_{o}$ .

For magnetic moments: $C o (III)$ complexes are low-spin diamagnetic ( $μ = 0$ ), whereas $C o (II)$ complexes are paramagnetic, meaning the magnetic moment increases during decomposition and decreases during oxidation.

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Options:(select one or more)

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