What is the colour of Cr(NH3)6 3+Watch
Does anybody know what the mark scheme answer is ? A2 chem
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