Metal-aqua ions Flashcards
What is a co-ordinate bond?
One substance donating a pair of electrons to another
When do metal-aqua complex ions form?
When metal ions dissolve in water, the water molecules form co-ordinate bonds with the metal ions
In general, how many water molecules bond in a metal-aqua complex?
6
Why are metal 3+ ions more acidic than metal 2+ ions?
- Metal 3+ ions have a higher charge density than metal 2+ ions
- Metal 3+ ions are much more polarising than the 2+ ions
- Metal 3+ ions attract electrons from the oxygen atoms from the co-ordinately bonded water molecules more strongly than the metal 2+ ions
- This means it is more likely an H+ ion will be released and then the solution will be more acidic
What is the general overall equation when metal aqua ions act as bronsted Lowry acids?
[M(H₂O)₆]³⁺ + 3H₂O M(OH)₃(H₂O)₃ + 3H₃O+
What is the first equation when a 3+ metal aqua ion complex reacts with water?
[M(H₂O)₆]³⁺ + H₂O [M(OH)(H₂O)₅]²⁺ + H₃O+
What is the second equation when a 3+ metal aqua ion complex reacts with water?
[M(OH)(H₂O)₅]²⁺ + H₂O [M(OH)₂(H₂O)₄]⁺ + H₃O+
What is the third equation when a 3+ metal aqua ion complex reacts with water?
[M(OH)₂(H₂O)₄]⁺+ H₂O M(OH)₃(H₂O)₃ + H₃O+
What can some metal hydroxides be?
Amphoteric
what does amphoteric mean?
They can act as both acids and bases
What colour is [Cu(H₂O)₆]²⁺?
Blue solution
What colour is [Fe(H₂O)₆]²⁺?
Green solution
What colour is [Fe(H₂O)₆]³⁺?
Yellow solution
What colour is [Al(H₂O)₆]³⁺?
Colourless solution
What is formed when [Cu(H₂O)₆]²⁺ reacts with OH- or NH₃?
Cu(OH)₂(H₂O)₄ + 2H₂O
What colour is Cu(OH)₂(H₂O)₄?
Blue precipitate
What is formed when excess OH- is added to [Cu(H₂O)₆]²⁺?
No change
Cu(OH)₂(H₂O)₄
Blue precipitate
What is formed when [Cu(H₂O)₆]²⁺ reacts with excess NH₃?
[Cu(NH₃)₄(H₂O)₂]²⁺ + 4H₂O
What colour is [Cu(NH₃)₄(H₂O)₂]²⁺?
Deep blue solution
What is formed when [Cu(H₂O)₆]²⁺ reacts with Na₂CO₃?
CuCO₃ + 6H₂O
What colour is CuCO₃?
Green-blue precipitate
What is formed when [Fe(H₂O)₆]²⁺ reacts with OH- or NH₃?
Fe(OH)₂(H₂O)₄ + 2H₂O
What is formed when excess OH- is added to [Fe(H₂O)₆]²⁺ ?
No change
Fe(OH)₂(H₂O)₄
Green precipitate
What is formed when [Fe(H₂O)₆]²⁺ reacts with excess NH₃?
No change
Fe(OH)₂(H₂O)₄
Green precipitate
What is formed when [Fe(H₂O)₆]²⁺ reacts with Na₂CO₃?
FeCO₃ + 6H₂O
What colour is Fe(OH)₂(H₂O)₄?
Green precipitate which goes brown standing in air
What colour is FeCO₃?
Green precipitate
What is formed when [Al(H₂O)₆]³⁺ reacts with OH- or NH₃?
Al(OH)₃(H₂O)₃ + 3H₂O
What colour is Al(OH)₃(H₂O)₃ ?
White precipitate
What is formed when [Al(H₂O)₆]³⁺ reacts with excess OH-?
[Al(OH)₄(H₂O)₂]-
What is formed when [Al(H₂O)₆]³⁺ reacts with excess NH₃?
[Al(OH)₄(H₂O)₂]-
Colourless solution
What is formed when [Al(H₂O)₆]³⁺ reacts with Na₂CO₃?
Al(OH)₃(H₂O)₃ + 3H₂O
Bubbles
What colour is [Al(OH)₄(H₂O)₂]-?
Colourless solution
What is formed when [Fe(H₂O)₆]³⁺ reacts with OH- or NH₃?
Fe(OH)₃(H₂O)₃ + 3H₂O
What colour is Fe(OH)₃(H₂O)₃?
Brown precipitate
What is formed when [Fe(H₂O)₆]³⁺ reacts with excess OH- or NH₃?
No further change
Fe(OH)₃(H₂O)₃
Brown precipitate
What is formed when [Fe(H₂O)₆]³⁺ reacts with Na₂CO₃?
Fe(OH)₃(H₂O)₃
Bubbles
