Chapter 24- Ions In Aqueous Solution Flashcards
Why are 3+ ions more acidic than 2+ ions?
3+ ions are smaller and more highly charged than 2+ ions so have a greater polarising power and distort water ligands.
This weakens O-H bond which breaks releasing H+ ion decreasing pH.
What is the reaction between 2+ ions and OH- drop-wise?
Deprotonation of two water ligands caused by 2OH- ions producing uncharged precipitate with 4 H2O and 2 OH ligands
What is the reaction between 3+ ions and OH- drop-wise?
Deprotonation of three water ligands caused by 3 OH- ions producing uncharged precipitate with 3 H2O and 3 OH ligands
What happens when excess OH- is added to Cr 3+ and Al 3+?
One proton is given up producing a negatively charged complex ion with 2 H2O and 4 OH ligands so they redissolve and a water molecule
Doesn’t do anything with other ions
What is the reaction between 2+ and 3+ ions and NH3 dropwise?
Ammonia accepts H+ ions to produce uncharged complexes with H2O and OH ligands and ammonium ions
What happens when excess NH3 is added to Cu 2+, Co 2+ and Cr 3+ ions?
Copper complex produced by dropwise reacts with 4 NH3 in ligand substitution which subs out 2 H2O and 2 OH- ligands
How do 2+ ions react with CO3 2- ions?
2+ ions are not acids so react to produce metal carbonate and water
How do 3+ ions react with CO3 2- ions?
One reaction: Deprotonation of 3+ complex ion occurs 3 times to produce 3 H+ ions
Another reaction: carbonate ions react with 2H+ ions to produce CO2 and H2O
Combine reactions for overall reaction
What happens when concentrated HCl is added to Cu 2+ ions?
Ligand substitution occurs involving Cl- and H2O ligands causing coordination number to decrease to four producing tetrahedral complex
What is the observation for Fe 2+ complex ions?
Pale green solution
What is the observation for Fe 2+ complexes?
Dark green precipitate
What is the observation for FeCO3?
Green precipitate
What is the observation for Cu 2+ complexes or complex ions?
Complex ions are pale blue solution
Complexes are pale blue solution
Complex with xs NH3 is dark blue solution
Complex with Cl- is yellow solution
What is the observation for CuCO3?
Bluey green precipitate
What is the observation for Fe 3+ complexes and complex ions?
Complexes are brown precipitate
Complex ions are brown solution
What is the observation for Fe 3+ reacting with carbonate ions?
Produces bubbles
What are the observations for Al 3+ complexes and complex ions?
Complexes are white precipitates
Complex ions are colourless solutions
What is the observation for Al 3+ ions reacting with carbonate ions?
Produces bubbles
