Aqueous Ions Flashcards
What is a complex ion
A positive metal ion surrounded by ligands. Ligands bind to central metal ion by coordinate bonds
Coordinate bond definition
A shared pair of electrons which have both come from the same atom
Ligand definition
An ion or molecule with a lone pair of electrons which can form a coordinate bond with a transition metal ion
Coordinate number definition
The number of coordinate bonds a transition metal ion forms
4 hexa aqua complex ions
[Cu(H2O)6]2+
[Fe(H2O)6]2+
[Fe(H2O)6]3+
[Al(H2O)6]3+
Iron(II) in aqueous solution formula and colour
[Fe(H2O)6] 2+ (aq)
Green solution
Copper (II) in aqueous solution formula and colour
[Cu(H2O)6]2+(aq)
Blue solution
Iron(III) in aqueous solution formula and colour
[Fe(H2O)6]3+(aq)
Purple solution
May look yellow- brown due to some [Fe(H2O)5(OH)]2+ (aq)
Aluminium (III) in aqueous solution formula and colour
[Al(H2O)6]3+(aq)
Colourless solution
Aluminium (III) in NaOH (aq) formula and colour
Al(H2O)3(OH)3 (s)
White precipitate
Aluminium (III) in excess NaOH (aq) formula and colour
[Al(OH)4]- (aq)
Colourless solution
Aluminium (III) in NH3 (aq) formula and colour
Al(H2O)3(OH)3 (s)
white precipitate
Aluminium (III) in excess NH3 (aq) formula and colour
no further change so still
Al(H2O)3(OH)3 (s)
white precipitate
Aluminium (III) in Na2CO3 (aq) formula and colour
Al(H2O)3(OH)3 (s)
White precipitate
And CO2 has evolved
Iron(II) in NaOH (aq) formula and colour
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
Iron(II) in NH3 (aq) formula and colour
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
Iron(II) in excess NaOH (aq) formula and colour
No further change so
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
Iron(II) in excess NH3(aq) formula and colour
No further change so
Fe(H2O)4(OH)2 (s)
Green ppt goes brown on standing in air
Iron(II) in Na2CO3 (aq) formula and colour
FeCO3 (s)
Green ppt
Copper(II) in NaOH (aq) formula and colour
Cu(H2O)4(OH)2(s)
Blue ppt
Copper(II) in excess NaOH (aq) formula and colour
No further change so Cu(H2O)4(OH)2(s)
Blue ppt
Copper(II) in NH3 (aq) formula and colour
Cu(H2O)4(OH)2(s)
Blue ppt
Copper(II) in excess NH3 (aq) formula and colour
[Cu(H2O)2(NH3)4]2+ (aq)
Depp blue solution
Copper(II) in Na2CO3 (aq) formula and colour
CuCO3 (s)
Blue- green ppt
Iron(III) in NaOH (aq) formula and colour
Fe(H2O)3(OH)3 (s)
Brown ppt ( may look orange-brown)
Iron(III) in excess NaOH (aq) formula and colour
No further change so
Fe(H2O)3(OH)3 (s)
Brown ppt ( may look orange-brown)
Iron(III) in NH3 (aq) formula and colour
Fe(H2O)3(OH)3 (s)
Brown ppt ( may look orange-brown)
Iron(III) in excess NH3 (aq) formula and colour
No further change so Fe(H2O)3(OH)3 (s)
Brown ppt ( may look orange-brown)
Iron(III) in Na2CO3 (aq) formula and colour
Fe(H2O)3(OH)3 (s)
Brown ppt ( may look orange-brown) and CO2 gas evolved
Reaction of Copper(II) with HCl (aq) product formula and colour
[CuCl4]2- (aq)
Yellow solution (may look green)
Relative acidity of metal-aqua ions and why
The 3+ ions are more acidic than 2+ as Fe3+ smaller and more highly charged than Fe2+, so Fe3+ is more polarising so strongly attracts the lone pair on the oxygen of the water ligands, in tune this weakens the O-H bond strength. So Fe(III) complex more easily realeases H+ ions making the solution acidic
The fe(II) complex doesn’t realease H+ ions
The character of metal hydroxides as basic or amphoteric
Aluminium hydroxide is amphoteric
It acts as a base when HCl
is added product is [Al(H2O)6]3+
Acts as an acid with NaOH added
Product [Al(H2O)2(OH)4]-
