Ligand Substitution: Colour Changes And Reactions Flashcards
What is the colour when copper (ii) sulphate is dissolved in water?
Pale blue
What is the precipitate seen when ammonia is initially added to Copper (ii) sulphate?
Cu(OH)2
What is formed when excess ammonia is added to Copper (ii) Sulphate?
[Cu(H2O)2(NH3)4]2+
What is the colour of [Cu(H2O)2(NH3)4]2+ solution?
Dark blue
Why do only 4 chloride ions substitute the 6 H2O ligands?
The chloride ligands are larger in size and therefore fewer chloride ligands can fit around the Cu2+ ion
What is the colour change when [Cu(H2O)6]2+ solution is added to an excess of concentrated HCL?
Pale blue to yellow
Why will an intermediate green solution be seen when adding conc. HCL to [Cu(H2O)6]2+?
The yellow product solution and reactant solution mixing as the reaction proceeds.
How does the coordination number change when adding conc. HCL to [Cu(H2O)6]2+
Coordination number decreases from 6 to 4.
What is the shape of the complex ion formed by adding conc. HCL to [Cu(H2O)6]
Tetrahedral
What dissolved compound forms [Cr(H2O)6]3+ ions?
KCr(SO4)2 • 12(H2O)
What colour solution does [Cr(H2O)6]3+ form?
Pale purple
What complex ion forms a green solution?
[Cr(H2O)5 SO4]+
When Chromium (iii) Sulfate is dissolved in water what complex ion is formed?
[Cr(H2O)5 SO4]+
What is the equation for ligand substitution of [Cu(H2O)6]2+ with ammonia?
[Cu(H2O)6]2+ (aq)+ 4NH3(aq) -> [Cu(NH3)4(H2O)2]2+ (aq) + 4 H2O
What is the colour change when excess ammonia is added to [Cr(H2O)6]3+?
pale purple -> purple
What is the complex ion product when excess ammonia is added to [Cr(H20)6]3+
[Cr(NH3)6]3+(aq)
What is the intermediate grey-green product formed when ammonia is added to [Cr(H2O)6]3+
Cr(OH)3
What is the equation of the reaction between excess conc. HCL and [Cu(H2O)6]2+?
[Cu(H2O)6]2+ (aq) + 4Cl-(aq) -> [CuCl4]2- (aq) + 6H2O(l)
What is the equation of the reaction between excess ammonia and [Cr(H2O)6]3+?
[Cr(H2O)6]3+(aq) + 6NH3(aq) -> [Cr(NH3)6]3+(aq) + 6H2O
What is the equation for the precipitation reaction with NaOH + Cu2+
Cu2+(aq) + 2OH-(aq) -> Cu(OH)2(s)
What is the colour change in the reaction with NaOH and Cu2+
blue solution -> blue precipitate
Which ions are insoluble in excess NaOH during precipitation reactions
Cu2+, Fe2+, Fe3+, Mn2+
What is the equation for the precipitation reaction with NaOH and Fe2+
Fe2+(aq) + 2OH-(aq) -> Fe(OH)2(s)
What is the equation for the precipitation reaction with NaOH and Fe2+ when in air
Fe(OH)2(s) -> Fe(OH)3(s)
What is the colour change in the precipitation reaction NaOH + Fe2+
pale green solution -> green precipitate
What colour change is observed when Fe2+ reacts with NaOH in air
turns brown at its surface
What is the equation for the precipitation reaction with NaOH and Fe3+
Fe3+(aq) + 3OH- (aq) -> Fe(OH)3(s)
What is the colour change observed for the precipitation reaction with NaOH and Fe3+
pale yellow solution -> orange/brown precipitate
What is the equation for the precipitation reaction between NaOH and Mn2+
Mn2+(aq) + 2OH-(aq) -> Mn(OH)2(s)
What is the colour change observed for the precipitation reaction with NaOH and Mn2+
Pale pink solution -> light brown precipitate
What happens to the colour of Mn(OH)3 in air
it darkens in standing air
What is the equation for the precipitate reaction with NaOH and Cr3+
Cr3+(aq) + 3OH-(aq) -> Cr(OH)3(s)
What is the colour change observed for the precipitate reaction between NaOH and Cr3+
pale purple -> grey/green precipitate
What is the equation for the precipitate reaction with Cr3+ and NaOH when excess NaOH has been added
Cr(OH)3(s) + 3OH-(aq) -> [Cr(OH)6]3-(aq)
What is the colour change observed for the precipitate reaction with Cr3+ and NaOH when excess NaOH has been added
grey/green precipitate -> dark green solution
