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