Ions in aqueous solutions

Question 1

[Cu(H2O)6]2+ colour

Answer 1

blue solution

Question 2

[Fe(H2O)6]2+ colour

Answer 2

Green solution

Question 3

[Al(H2O)6]3+ colour

Answer 3

Colourless

Question 4

[Fe(H2O)6]3+ colour

Answer 4

Purple

Question 5

What happens when you react the metal-aqua ions with OH- or NH3

Answer 5

Acid-base reaction
Protons are lost from metal-aqua ion until complex becomes uncharged

Question 6

What happens when you react [Cu(H2O)6]2+ with OH- or NH3

Answer 6

[Cu(H2O)4(OH)2] formed
Light blue ppt

Question 7

What happens when you react [Fe(H2O)6]2+ with OH- or NH3

Answer 7

[Fe(H2O)4(OH)2] formed
Green ppt

Question 8

What happens when you react [Al(H2O)6]3+ with OH- or NH3

Answer 8

[Al(H2O)3(OH)3] formed
White ppt
Dissolves in excess OH

Question 9

What happens when [Al(H2O)3(OH)3] is dissolved in excess OH

Answer 9

[Al(OH4)(H2O)2]- is formed
Colourless

Question 10

What happens when [Cu(H2O)4(OH)2] is reacted with excess NH3

Answer 10

[Cu(NH3)4(H2O)2]2+ formed
deep blue solution

Question 11

Explain why all of the metal hydroxide ppts redissolve in acid

Answer 11

The metal hydorxide ppts accept the protons being converted back into metal-aqua ions

Question 12

How do the metal aqua ions differ in their reactions with carbonate ions

Answer 12

2+ ions form a MCO3 ppt and 6H2O
3+ ions react with carbonate ions to produce M(OH)3(H2O)3 ppt, 3CO2 and 3H2O

Question 13

[Cu(H2O)6]2+ + CO3 2-

Answer 13

CuCO3 + 6H2O Blue ppt

Question 14

[Fe(H2O)6]2+ + CO3 2-

Answer 14

FeCO3 + 6H2O gREEN PPT

Question 15

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

Answer 15

2Fe(OH)3(H2O)3 +3CO2 + 3H2O BROWN PPT AND BUBBLING

Question 16

2[Al(H2O)6]3+ + 3CO3 2-

Answer 16

2Al(OH)3(H2O)3 +3CO2 + 3H2O WHITE PPT AND BUBBLING