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    http://filestore.aqa.org.uk/subjects...5-QP-JUN15.PDF

    For question 7, I don't quite understand/appreciate how to write the ionic equation for these reactions. Surely the 'normal' equations can't be simplified?

    I would have said

    [Cr(H2O)3(OH)3] + 3H+ ---> [Cr(H2O)6]3+ + 3OH-

    and

    [Cr(H2O)3(OH)3] + 3OH- ---> [Cr(OH)6]3- + 3H2O

    ????

    Thanks
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    (Original post by hi-zen-berg)
    http://filestore.aqa.org.uk/subjects...5-QP-JUN15.PDF

    For question 7, I don't quite understand/appreciate how to write the ionic equation for these reactions. Surely the 'normal' equations can't be simplified?

    I would have said

    [Cr(H2O)3(OH)3] + 3H+ ---> [Cr(H2O)6]3+ + 3OH-

    and

    [Cr(H2O)3(OH)3] + 3OH- ---> [Cr(OH)6]3- + 3H2O

    ????

    Thanks
    Your equations are fine - they are the ionic equations
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    (Original post by GDN)
    Your equations are fine - they are the ionic equations
    Thanks for the feedback; I thought so but the mark scheme doesn't seem to agree with me? Quoting

    Cr(OH)3 + 3H2O + 3H+ → [Cr(H2O)6]3+

    and

    Cr(OH)3 + 2H2O + OH– → [Cr(H2O)2(OH)4]–
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    (Original post by hi-zen-berg)
    Thanks for the feedback; I thought so but the mark scheme doesn't seem to agree with me? Quoting

    Cr(OH)3 + 3H2O + 3H+ → [Cr(H2O)6]3+

    and

    Cr(OH)3 + 2H2O + OH– → [Cr(H2O)2(OH)4]–
    AQA accepts a variety of equations for these changes - in my opinion yours are the most consistent since they emphasise that the various species are 6 coordinate
 
 
 
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