6: Reaction of Ions in Aqueous Solution Flashcards
How many H2O molecules bind to a metal ion?
6
How do we name metal aqua ions?
Hexaaqua for the 6 H2O
Then the metal name
Eg: Hexaaquacopper
What type of bonds are found in metal aqua ions?
Coordinate
Give 2 hydrolysis equations, starting with [Fe(H2O)6]2+, that show the acidity. The final product should be [Fe(OH)2(H2O)4]
[Fe(H2O)6]2+ + H2O = [Fe(H2O)5(OH)]+ + H3O+
[Fe(H2O)5(OH)]+ + H2O = [Fe(OH)2(H2O)4] + H3O+
Give 3 hydrolysis equations, starting with [Al(H2O)6]3+, that show the acidity of 3+ ions. The final product should be [Al(OH)3(H2O)3]
[Al(H2O)6]3+ + H2O = [Al(H2O)5(OH)]2+ + H3O+
[Al(H2O)5(OH)]2+ + H2O = [Al(OH)2(H2O)4]+ + H3O+
[Al(OH)2(H2O)4]+ + H2O = [Al(OH)3(H2O)3] + H3O+
Give 2 reasons why 3+ ions are more acidic.
They have a larger charger and are therefore smaller
3+ Ions are more polarising
What does it mean to say that 3+ ions are more polarising to water ligands?
They have a higher charge and therefore attract more electrons from the oxygen in the water molecule, in the coordinate bond
When OH- is added during hydrolysis, how does this affect equilibrium?
This removes H3O+ ions, so equilibrium shifts right to try and raise concentration of these ions.
Give an overall hydrolysis equation for [Fe(H2O)6]3+ with NH3
[Fe(H2O)6]3+ + 3NH3 = [Fe(OH)3(H2O)3] + 3NH4+
Give an overall hydrolysis equation for [Cu(OH)6]4- with NH3
[Cu(OH)6]4- + 4NH3 = [Cu(NH3)4(H2O)2]2+ + 6OH-
Give a general overall ionic equation for the hydrolysis of metal aqua ion [M(H2O)6]2+ using Na2CO3
[M(H2O)6]2+ + CO3 2- = MCO3 + 6H2O
What colour will the precipitate produced be when NaOH is added to a solution of Fe3+ ions?
Brown precipitate
Give the overall reverse hydrolysis equation for the formation of [Fe(H2O)6]3+ from Fe(OH)3(H2O)3
Fe(OH)3(H2O)3 + 3H+ =[Fe(H2O)6]3+
What does amphoteric mean?
Where a substance can act as both an acid or a base.
Give an equation for Al(OH)3(H2O)3 to form [Al(OH)4(H2O)2]- where it acts as a Bronsted Lowry acid.
Al(OH)3(H2O)3 + OH- = [Al(OH)4(H2O)2]- + H2O
Give an equation showing Al(OH)3(H2O)3 acting as Bronsted Lowry base.
Al(OH)3(H2O)3 + 3H+ = [Al(H2O)6]3+
If you add some OH- to [Fe(H2O)6]2+, what will you observe before and after?
What will you observe if OH- is added in excess?
Green solution to turns to green precipitate
No visible change
If you add some OH- to [Cu(H2O)6]2+, what will you observe before and after?
What will you observe if OH- is added in excess?
Blue solution to blue precipitate
No visible observation
If you add some OH- to [Fe(H2O)6]3+, what will you observe before and after?
What will you observe if OH- is added in excess?
Orange solution to brown precipitate
No visible observation
If you add some OH- to [Al(H2O)6]3+, what will you observe before and after?
What will you observe if OH- is added in excess?
Colourless solution to white precipitate
No visible reaction
If you add some NH3 to [Fe(H2O)6]2+, what will you observe before and after?
What will you observe if NH3 is added in excess?
Green solution to green precipitate
No visible change
If you add some NH3 to [Cu(H2O)6]2+, what will you observe before and after?
What will you observe if NH3 is added in excess?
Blue solution to blue precipitate
Deep blue precipitate
If you add some NH3 to [Fe(H2O)6]3+, what will you observe before and after?
What will you observe if NH3 is added in excess?
Orange solution to brown precipitate
No visible change
If you add some NH3 to [Al(H2O)6]3+, what will you observe before and after?
What will you observe if NH3 is added in excess?
Colourless solution to white precipitate
