IAL EDEXCEL CHEM TRANSITION METAL REACTIONS

cobalt with alkali

- PINK solution to BLUE precipitate

- deprotonation

- if left to stand, returns to pink

cobalt with ammonia

- PINK solution to BLUE precipitate

- deprotonation

- if left to stand, will return to pink

cobalt with excess ammonia

- BLUE ppt to YELLOW solution

- ligand exchange

- if left to stand, solution oxidises and becomes brown

cobalt with HCl

- PINK solution to BLUE solution

- ligand exchange

- change in coordination number

iron (II) with alkali

- PALE GREEN solution to GREEN precipitate

- deprotonation

- if left to stand, oxidises to brown

iron (II) with ammonia

- PALE GREEN solution to GREEN precipitate

- deprotonation

- if left to stand, will oxidise to brown

iron (III) with alkali

- YELLOW solution to BROWN precipitate

- deprotonation

iron (III) with ammonia

- YELLOW-BROWN solution to BROWN precipitate

- deprotonation

chromium (III) with alkali

- GREEN solution to GREEN precipitate

- deprotonation

- if alkali is more concentrated, will deprotonate further, but no change in colour

chromium (III) with excess alkali

- GREEN precipitate to GREEN solution

chromium (III) with ammonia

- GREEN solution to GREEN precipitate

- deprotonation

chromium (III) with excess ammonia

- GREEN precipitate to VIOLET solution

- ligand exchange

- dissolving is slow

chromium (III) with H2O2

- GREEN solution to YELLOW solution

- Cr(III) to Cr(VI)

- oxidation

chromate (VI) with H+

- YELLOW solution to ORANGE solution

- chromate (VI) to dichromate (VI)

dichromate (VI) with zinc

- ORANGE solution to GREEN solution to BLUE solution

- reduction

- dichromate (VI) to Cr(III) to Cr(II)

manganese (II) with alkali

- PALE PINK solution to PALE BROWN precipitate

- deprotonation

- if left to stand, oxidises to dark brown, then very dark brown

manganese (II) with ammonia

- PALE PINK solution to PALE BROWN precipitate

- deprotonation

- if left to stand, will oxidise to dark brown, then very dark brown

vanadium (II) to vanadium (III)

- PURPLE solution to GREEN solution

- oxidation

- V2+ to V3+

- undone by adding zinc

vanadium (III) to oxovanadium (IV)

- GREEN solution to BLUE solution

- oxidation

- V3+ to (VO)2+

- undone by adding zinc

oxovanadium (IV) to dioxovanadium (V)

- BLUE solution to YELLOW solution

- oxidation

- (VO)2+ to (VO2)+

- undone by adding zinc

nickel (II) in alkali

- GREEN solution to GREEN precipitate

- deprotonation

nickel (II) in ammonia

- GREEN solution to GREEN precipitate

- deprotonation

nickel (II) in excess ammonia

- GREEN precipitate to BLUE solution

- ligand exchange

zinc (II) in alkali

- COLOURLESS solution to WHITE precipitate

- deprotonation

- no colour as d-block isn't split!

- product (zinc hydroxide) reacts with acid (with excess alkali)

zinc (II) in excess alkali

- WHITE precipitate to COLOURLESS solution

- ligand exchange

zinc (II) in ammonia

- COLOURLESS solution to WHITE precipitate

- deprotonation

zinc (II) in excess ammonia

- WHITE precipitate to COLOURLESS solution

- ligand exchange