Leah.J
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I swear every source gives a different answer . Is it purple ? or yellow ? or green ?
Does anybody know what the mark scheme answer is ? A2 chem
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CuriosityYay
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[Cr(H2O)6]3+ + 3OH- (or 3NH3) -> [Cr(H2O)3(OH)3] + 3H2O (or 3NH4+)
green or violet solution forms a green precipitate

an excess of NaOH causes the green precipitate to dissolve and form a green solution of:
[Cr(H2O)2(OH)4]- or [Cr(OH)6]3- (depending on concentration of NaOH)

an excess of NH3 causes the green precipitate to slowly dissolve giving a violet or purple solution.
[Cr(H2O)3(OH)3] + 6NH3 -> [Cr(NH3)6]3+ + 3H2O + 3OH-

Source: (Endorsed by Edexcel) A level CHEMISTRY Book 2 (A2) by Cliff Curtis, Jason Murgatroyd and David Scott
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Velaikkaran
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If you add nh3 liquidTo cr3 It’s yellow If you add nh4oh It’s purple
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Pigster
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(Original post by Leah.J)
I swear every source gives a different answer . Is it purple ? or yellow ? or green ?
Does anybody know what the mark scheme answer is ? A2 chem
Which spec?
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