Edexcel A-Level Chemistry Transition Metal Colours Questions and Answers

Edexcel A-Level Chemistry Transition Metal Colours Questions and Answers What colours are MnO4- [+7] , MnO42- [+6], and Mn2+ [+2], in an aqueous complex? Purple, Green and Pale Pink respectively What colours are Ti3+ , Ti2+ in an aqueous complex Purple and Violet respectively What colours are VO2+ , VO2+ , V3+ and V2+ in an aqueous complex Yellow, Blue, Green, and Violet respectively What colours are CrO72- and Cr3+ in an aqueous complex Orange and green respectively What colours are Fe3+ and Fe2+ in an aqueous complex Yellow and pale green respectively What colour is Co2+ in an aqueous complex Pink What colour is Ni2+ in an aqueous complex Green What colour is Cu2+ in an aqueous complex Pale blue What transition metals cause a green aqueous complex(3) V3+ , Cr3+ , Ni2+ What transition metals cause purple aqueous complexes (4) (specify if violet ) PURPLE: Ti3+ , MnO4- , VIOLET: Ti2+ , V2+ What transition metal causes a pink aqueous complex (specify if pale)(2) PINK: Co2+ PALE PINK: Mn2+ What transition metal causes a pale green aqueous complex(1) Fe2+ What transition metals cause a yellow aqueous complex(2) Fe3+ , VO2^+ What transition metal causes a blue aqueous complex (specify if pale)(2) BLUE: VO^2+ PALE BLUE: Cu2+ What transition metal causes a orange aqueous complex Cr2O72- What colour is [Cu(OH)2(H2O)4] Blue precipitate What color is [Cu(NH3)4(H2O)2]2+ Deep blue solution What colour is [Fe(OH)2(H20)4], how does this colour change over time? Green precipitate, darkens over time As is oxidised by water and oxygen it goes Brown-Orange , (Iron(III) Hydroxide) What colour is [Fe(OH)3(H20)3], how does it change over time? Orange, darkens over time What colour is [Co(OH)2(H20)4], how does it change over time? Blue changes over time to brown What colour is [Co(NH3)6]2+ how does it change over time? a yellow-brown solution which can be oxidised to [Co(NH3)6]3+ What colour/state is copper(II)hydroxide ? Blue precipitate What colour/state is the compound made when copper(II)hydroxide is reacted with excess ammonia ? Deep blue, soloution [Cu(NH3)4(H2O)2]2+ What colour/state is iron(II)hydroxide Green precipitate, darkens on standing What colour/state is Iron(III)hydroxide Orange precipitate darkens on standing What colour/state is cobalt(II)hydroxide Blue precipitate (turns brown if left) What colour/state is [Co(NH3)6]3+ Brown solution What colour/state is [Cr(NH3)6)]3+ Purple solution What colour/state is chromium(III)hydroxide Grey green precipitate What colour/state is [Cr(OH)6]3- Dark green solution How would you prepare to make chromium(II) ethanoate Put zinc mesh and sodium dischromate into conical flask Add HCl zinc reacts with acid to make hydrogen; allow to escape through rubber tube to waterbath Once solution is clear blue (Cr2+ has been made), close rubber tube so hydrogen cant escape Pressure will cause chromium(II) to escape through tubing into sodium ethanoate, once a red precipitate forms chromium ethanoate has been made Filter and wash the precipitate with water and ethanol then ether Chromium ethanoate must be kept in inert conditions to prevent oxidation What colour is copper(II)chloride Yellow What colour is cobalt(II)chloride Pale pink