AQA A Level Chemistry Transition Metals – Colours Questions and Answers

AQA A Level Chemistry Transition Metals – Colours Questions and Answers Colour of MnO4- (+7 oxidation state) purple Colour of CrO7 2- (+6 oxidation state) orange Colour of V(O2)+ (+5 oxidation state) yellow Colour of VO 2+ (+4 oxidation state) blue Colour of V 3+ (+3 oxidation state) green Colour of Cr 3+ (+3 oxidation state) green/violet Colour of Fe 3+ (+3 oxidation state) yellow Colour of V 2+ (+2 oxidation state) violet Colour of Mn 2+ (+2 oxidation state) pale pink Colour of Fe 2+ (+2 oxidation state) pale green Colour of Co 2+ (+2 oxidation state) pink Colour of Ni 2+ (+2 oxidation state) green Colour of Cu 2+ (+2 oxidation state) blue Cr 3+ are violet when... they are surrounded by 6 water ligands Cr 3+ are green when... the 6 water ligands are substituted If [Cu(H2O)6]2+ absorbs light from the red end of the spectrum... blue will be produced Colour of [Fe(H2O)6]2+ pale green Colour of [Fe(H2O)6]3+ yellow Colour of [V(H2O)6]2+ violet Colour of [V(H2O)6]3+ green Colour of [Cu(H2O)6]2+ blue Colour of [CuCl4]2- yellow Colour of [Co(H2O)6]2+ pink Colour of [Co(NH3)6]2+ straw coloured [Cu(H2O)6]2+ with OH- or NH3 blue ppt [Cu(H2O)6]2+ with excess OH- no change [Cu(H2O)6]2+ with excess NH3 deep blue solution [Cu(H2O)6]2+ with Na2CO3 green-blue ppt [Fe(H2O)6]2+ with OH- or NH3 green ppt [Fe(H2O)6]2+ with excess OH- no change [Fe(H2O)6]2+ with excess NH3 no change [Fe(H2O)6]2+ with Na2CO3 green ppt [Al(H2O)6]3+ with OH- or NH3 white ppt