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The Co²⁺/ Co(SCN)₄²⁻ Equilibrium

  • Page ID
    3065
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    Chemical Concept Demonstrated

    • The tendency for ionic substrates to extract into more polar solvents

    Demonstration

    75 mL of water is poured into a funnel.

    A blue ether solution, made up of KSCN, CoCl2, and ethyl ether, is added to the funnel.

    The funnel is stoppered and the contents inside are shaken.

    extract.gif

    Observations

    The water layer changes into a pink solution at the bottom of the separatory funnel.

    Explanation

    Water is more polar than ethyl ether. Some of the Co2+ ions are extracted into the water layer from the Co(SCN)4 2-complex ions formed in the ether solution. The presence of Cl - can be seen by adding silver nitrate (AgNO3) solution until a white precipitate forms in the water layer at the bottom of the separatory funnel.


    The Co²⁺/ Co(SCN)₄²⁻ Equilibrium is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by George Bodner.

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