2.6 Reactions of aqueous ions Flashcards
What is formed when Fe²⁺ reacts with water?
Forms [Fe(H₂O)₆]²⁺
Hexa-aqua iron
What is formed when Cu²⁺ reacts with water?
Forms [Cu(H₂O)₆]²⁺
Hexa-aqua copper
What is formed when Fe³⁺ reacts with water?
Forms [Fe(H₂O)₆]³⁺
Hexa-aqua iron
What is formed when Al³⁺ reacts with water?
Forms [Al(H₂O)₆]³⁺
Hexa-aqua aluminium
Which is more acidic [M(H₂O)₆]³⁺ or [M(H₂O)₆]²⁺?
[M(H₂O)₆]³⁺
Explain why [M(H₂O)₆]³⁺ is more acidic?
- Has a higher charge and a smaller size.
- Therefore, the 3+ charge is more polarising.
- This attracts the e¯ from the oxygen lone pair on water ligands.
- This weakens the O-H bond on the water ligands.
- Makes it easier for the release of H⁺ from these bonds.
- H⁺ dissociates more, and therefore is more acidic.
How does [Fe(H₂O)₆]²⁺ react with a little bit of NaOH/NH₃?
- Partial hydrolysis of water ligands.
- Results in neutralisation.
[Fe(H₂O)₆]²⁺ + OH¯/NH₃ →
[Fe(OH)₂(H₂O)₄] + 2H₂O
What is the observation for [Fe(H₂O)₆]²⁺ + OH¯/NH₃?
Green precipitate (solution)
How does [Cu(H₂O)₆]²⁺ react with a little bit of NaOH/NH₃?
- Partial hydrolysis of water ligands.
- Results in neutralisation.
[Cu(H₂O)₆]²⁺ + OH¯/NH₃ →
[Cu(OH)₂(H₂O)₄] + 2H₂O
What is the observation for [Cu(H₂O)₆]²⁺ + OH¯/NH₃?
Blue precipitate (solution)
How does [Fe(H₂O)₆]²⁺react in excess OH¯/NH₃?
Same as in a little bit, just neutralisation.
How does [Cu(H₂O)₆]²⁺ react in excess OH¯?
Same as in a little bit, just neutralisation.
How does [Fe(H₂O)₆]³⁺ react with a little bit of NaOH/NH₃?
- Partial hydrolysis of water ligands.
- Results in neutralisation.
How does [Al(H₂O)₆]³⁺ react with a little bit of NaOH/NH₃?
- Partial hydrolysis of water ligands.
- Results in neutralisation.
[Fe(H₂O)₆]³⁺ + OH¯ / NH₃→
[Fe(OH)₃(H₂O)₃] + 3H₂O
[Al(H₂O)₆]³⁺ + OH¯/NH₃ →
[Al(OH)₃(H₂O)₃] + 3H₂O
What is the observation for [Fe(H₂O)₆]³⁺ + OH¯/NH₃?
Brown precipitate (solution)
What is the observation for [Al(H₂O)₆]³⁺ + OH¯/NH₃?
White precipitate (solution)
How does react [Fe(H₂O)₆]³⁺ in excess OH¯/NH₃?
Same as in a little bit, just neutralisation.
How does react [Al(H₂O)₆]³⁺ in excess OH¯?
Forms [Al(OH)₄]¯
How does [Fe(H₂O)₆]²⁺ react in excess NH₃?
Same as in a little bit, just neutralisation.
How does [Cu(H₂O)₆]²⁺ react in excess NH₃?
- Neutralisation to form [Cu(OH)₂(H₂O)₄]
- Then does ligand substitution to form [Cu(NH₃)₄(H₂O)₂]²⁺
What is the observation for [Cu(H₂O)₆]²⁺ + excess NH₃?
Dark Blue solution
How does react [Al(H₂O)₆]³⁺ in excess NH₃?
Same as in a little bit, just neutralisation.
What is the observation for [Al(H₂O)₆]³⁺ + excess OH¯?
Colourless solution (see-through)
How does [Al(H₂O)₆]³⁺ react with CO₃¯?
- Neutralisation
Forms [Al(OH)₃(H₂O)₃]
What the observation for [Al(H₂O)₆]³⁺ + CO₃¯?
White precipitate + CO₂
How does [Fe(H₂O)₆]³⁺ react with CO₃¯?
- Neutralisation
Forms [Fe(OH)₃(H₂O)₃]
What the observation for [Fe(H₂O)₆]³⁺ + CO₃¯?
Brown precipitate + CO₂
How does [Fe(H₂O)₆]²⁺ react with CO₃¯?
Forms SALT + WATER
[Fe(H₂O)₆]²⁺ + CO₃¯ =
FeCO₃ + 6H₂O
What the observation for [Fe(H₂O)₆]²⁺ + CO₃¯?
Green precipitate
How does [Cu(H₂O)₆]²⁺ react with CO₃¯?
Forms SALT + WATER
[Cu(H₂O)₆]²⁺ + CO₃¯ =
CuCO₃ + 6H₂O
What the observation for [Cu(H₂O)₆]²⁺ + CO₃¯?
Blue precipitate