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    I found this question in a paper3b specimen paper for As Chemistry from Edexcel.

    Compound C contains an ion and cation. Certain tests were carried out on the compound:

    Tests:

    a) Flame Test

    Result: light green coloured flame

    b) Heat on C

    Result: Brown Gas Evolved
    Relights glowing splint

    c) Dissolve C in Water

    Result colourless solution

    d) Add dilute Sulphuric Acid to a solution of C

    Result: White ppt.

    e) Add excess NaOH to the solution of C

    Result: Faint white ppt. insoluble in excess



    The question requires me to fill in the inferences. I know that a) indicates the presence of barium ions. b) suggests bromide ions are present and oxygen was evolved. d) confirms the presence of Barium ions, however I have no idea what to infer from c) and e). I am aware that the compund is Barium Bromate.

    Thanks in advance for any help
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    (Original post by mubinchoudhury)
    I found this question in a paper3b specimen paper for As Chemistry from Edexcel.

    Compound C contains an ion and cation. Certain tests were carried out on the compound:

    Tests:

    a) Flame Test

    Result: light green coloured flame

    b) Heat on C

    Result: Brown Gas Evolved
    Relights glowing splint
    Brown gas: could be NO2. Relights glowing splint: definately oxygen. The nitrates of group 2 produce both these gases on heating

    c) Dissolve C in Water

    Result colourless solution
    sorry, not sure what this would infer Yes of course I do. See below :rolleyes:

    d) Add dilute Sulphuric Acid to a solution of C

    Result: White ppt.

    e) Add excess NaOH to the solution of C

    Result: Faint white ppt. insoluble in excess
    Could be Mg Li Ba Sr or Ca


    The question requires me to fill in the inferences. I know that a) indicates the presence of barium ions. b) suggests bromide ions are present and oxygen was evolved. d) confirms the presence of Barium ions, however I have no idea what to infer from c) and e). I am aware that the compund is Barium Bromate.

    Thanks in advance for any help
    Cation: definately Barium
    Anion: Could be nitrate (NO3-)

    Hope this helps!
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    The inference from c) is that the metal ion is not a transition metal and the salt is soluble.
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    It's barium nitrate.
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    (Original post by Ralfskini)
    The inference from c) is that the metal ion is not a transition metal and the salt is soluble.
    Of course! *bangs forehead on desk repeatedly* I should know that. Uncoloured solution: not a d block ion.
 
 
 
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