3.2.6 Reactions of aqueous ions Flashcards
Coordinate bond definition
A shared pair of electrons where the electrons have both come from the same atom
Ligand definition
An ion or molecule with a lone pair of electrons that can form a coordinate bond with a transition metal ion
Complex ion definition
A central atom or ion surrounded by ligands
Coordinate number definition
The number of coordinate bonds a transition metal can form
Why are the ions called hexa aqua complex ions?
They are surrounded by water
What is the colour of the [CU(H2O)6]2+ ion solution?
Blue solution
What is the colour of the [Fe(H2O)6]2+ ion solution?
Pale green solution
What is the colour of the [Fe(H2O)6]3+ ion solution?
Purple solution, but looks yellow/brown
What is the colour of the [Al(H2O)6]3+ ion solution?
Colourless solution
What is different about the aluminium ion compared to all the other aqueous ions?
It is not a transition metal, but behaves like one
Why is Fe3+ more acidic than Fe2+?
Fe3+ is more highly charged
Fe3+ is more polarising
Fe3+ strongly attracts the lone pair on the oxygen of the water ligand
This weakens the O-H bond strength
The Fe3+ complex more easily releases H+ ions, making the solution more acidic
What its the equation that shows Fe3+ acting as an acid?
[Fe(H2O)6]3+ –> [Fe(H2O)5(OH)]2+ + H+
Equation of [Fe(H2O)6]2+ reacting with Na2CO3 and the observation
[Fe(H2O)6]2+ + CO3 2- –> FeCO3 + 6H2O
Green solution forms green precipitate
Equation of [Fe(H2O)6]2+ reacting with NaOH and the observation
[Fe(H2O)6]2+ + 2OH- –> [Fe(H2O)4(OH)2] + 2H2O
Green solution forms green precipitate
Equation of [Fe(H2O)6]2+ reacting with NH3 and the observation
[Fe(H2O)6]2+ + 2NH3 –> [Fe(H2O)4(OH)2] + NH4+
Green solution forms green precipitate
Equation of [Cu(H2O)6]2+ reacting with Na2CO3 and the observation
[Cu(H2O)6]2+ + CO3 2- –> CuCO3 + 6H2O
Blue solution forms blue precipitate
Equation of [Cu(H2O)6]2+ reacting with NaOH and the observation
[Cu(H2O)6]2+ + 2OH- –> [Cu(H2O)4(OH2)] + 2H2O
Blue solution forms blue precipitate
Equation of [Cu(H2O)6]2+ reacting with NH3 (dropwise) and the observation
[Cu(H2O)6]2+ + 2NH3 –> [Cu(H2O)4(OH)2] + NH4+
Blue solution forms blue precipitate
Equation of [Cu(H2O)6]2+ reacting with excess NH3 and the observation
[Cu(H2O)6]2+ + 4NH3 –> [Cu(H2O)2(NH3)4]2+ +4H2O
Blue precipitate forms dark blue solution
Equation of [Fe(H2O)6]3+ reacting with Na2CO3 and the observation
2[Fe(H2O)6]3+ + 3CO3 2- –> 2[Fe(H2O)3(OH)3] + 3CO2 + 3H2O
Yellow brown solution forms brown precipitate and effervescence
Equation of [Fe(H2O)6]3+ reacting with NaOH and the observation
[Fe(H2O)6]3+ + 3OH- –> [Fe(H2O)3(OH)3] + 3H2O
Yellow brown solution forms brown precipitate
Equation of [Fe(H2O)6]3+ reacting with NH3 and the observation
[Fe(H2O)6]3+ + 3NH3 –> [Fe(H2O)3(OH)3] + 3NH4+
Yellow brown solution forms brown precipitate
Equation of [Al(H2O)6]3+ reacting with Na2CO3 and the observation
2[Al(H2O)6]3+ + 3CO3 2- –> 2[Al(H2O)3(OH)3] + 3CO2 +H2O
Colourless solution forms what precipitate and effervescence
Equation of [Al(H2O)6]3+ reacting with NaOH and the observation
[Al(H2O)6]3+ + 3OH- –> [Al(H2O)3(OH)3] + 3H2O
Colourless solution forms white precipitate
Equation of [Al(H2O)6]3+ reacting with excess NaOH and the observation
[Al(H2O)3(OH)3] + OH- –> [Al(H2O)2(OH)4]- + H2O
White precipitate dissolves to form a colourless solution
Equation of [Al(H2O)6]3+ reacting with NH3 and the observation
[Al(H2O)6]3+ + 3NH3 –> [Al(H2O)3(OH)3] + 3NH4+
Colourless solution forms white precipitate
Show aluminium hydroxide acting as a base
[Al(H2O)3(OH)3] + 3H+ –> [Al(H2O)6]3+
Show aluminium hydroxide acting as an acid
[Al(H2O)3(OH)3] + OH- –> [Al(H2O)2(OH)4]- + H2O
