3.2.6 REACTIONS OF IONS IN AQUEOUS SOLUTION

Describe the reaction of [Fe(H2O)6] 2+ with NaOH / NH3 stating equations, and state the colour of the species formed.

[Fe(H2O)6] 2+ + 2OH- → [Fe(H2O)4(OH)2] + 2H2O

[Fe(H2O)6] 2+ + 2NH3 → [Fe(H2O)4(OH)2] + 2NH4+

[Fe(H2O)4(OH)2](s) → green precipitate

Describe the reaction of [Cu(H2O)6] 2+ with NaOH / NH3 stating equations, and state the colour of the species formed.

[Cu(H2O)6] 2+ + 2OH- → [Cu(H2O)4(OH)2] + 2H2O

[Cu(H2O)6] 2+ + 2NH3 → [Cu(H2O)4(OH)2] + 2NH4+

[Cu(H2O)4(OH)2] → light blue precipitate

Describe the reaction of [Fe(H2O)6] 3+ with NaOH / NH3 stating equations, and state the colour of the species formed.

[Fe(H2O)6] 3+ + 3OH- → [Fe(H2O)3(OH)3] + 3H2O

[Fe(H2O)6] 3+ + 3NH3 → [Fe(H2O)3(OH)3] + 3NH4+

[Fe(H2O)3(OH3](s) → brown precipitate

Describe the reaction of [Al(H2O)6] 3+ with NaOH / NH3 stating equations, and state the colour of the species formed.

[Al(H2O)6] 3+ + 3OH- → [Al(H2O)3(OH)3] + 3H2O

[Al(H2O)6] 3+ + 3NH3 → [Al(H2O)3(OH)3] + 3NH4+

[Al(H2O)3(OH)3](s) → white precipitate

Describe the reaction of [Fe(H2O)6] 2+ with Na2CO3 stating equations, and state the colour of the species formed.

[Fe(H2O)6] 2+ + CO3 2- → FeCO3 + 6H2O

FeCO3 (s) → green precipitate

Describe the reaction of [Cu(H2O)6] 2+ with Na2CO3 stating equations, and state the colour of the species formed.

[Cu(H2O)6] 2+ + CO3 2- → CuCO3 + 6H2O

CuCO3 (s) → blue/green precipitate

Describe the reaction of [Fe(H2O)6] 3+ with Na2CO3 stating equations, and state the colour of the species formed.

2[Fe(H2O)6] 3+ + 3CO3 2- → 2[Fe(H2O)3(OH)3] + 3H2O + 3CO2

[Fe(OH)3(H2O)3](s) → brown precipitate

- bubbles (of gas) / effervescence / fixx

Describe the reaction of [Al(H2O)6] 3+ with Na2CO3 stating equations, and state the colour of the species formed.

2[Al(H2O)6] 3+ + 3CO2 2- → 2[Al(H2O)3(OH)3] + 3H2O + 3CO2

[Al(OH)3(H2O)3](s) → white precipitate

Describe the reaction of [Fe(H2O)6] 2+ with Cl- ions, stating equations, and state the colour of the species formed.

[Fe(H2O)6] 2+ + 4Cl- → [FeCl4]2- + 6H2O

[FeCl4] 2- = yellow solution

Describe the reaction of [Cu(H2O)6] 2+ with Cl- ions, stating equations, and state the colour of the species formed.

[Cu(H2O)6] 2+ + 4Cl- → [CuCl4] 2- + 6H2O

[CuCl4] 2- = green solution

Describe the reaction of [Fe(H2O)6] 3+ with Cl- ions, stating equations, and state the colour of the species formed.

[Fe(H2O)6] 3+ + 4Cl- → [FeCl4]- + 6H2O

yellow / brown solution

Describe the reaction of [Al(H2O)6] 3+ with Cl- ions, stating equations, and state the colour of the species formed.

[Al(H2O)6] 3+ + 4Cl- → [AlCl4]- + 6H2O

colourless solution