HELP! Chemistry Paper has me confused!!

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mubinchoudhury
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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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The Albatross
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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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Ralfskini
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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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hornblower
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It's barium nitrate.
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The Albatross
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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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