The D-And-f-Block Elements

  • Question
    CBSEENCH12010572

    Give reason:

    E° value for a Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.

    Solution

    Mn3+/ Mn2+ has large + value because Mn3+ reduced to Mn+2 which has a half-filled d-orbital configuration ([Ar]4s03d5).

    On the other hands, Fe3+/ Fe2+ has small +ve value because Fe3+ is much more stable than Fe2+. Electronic configuration of Fe3+ is [Ar]4s2 3d5 and Fe2+ [Ar]4s2 3d6.

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