Reactions of Ions in Aqueous Solutions

Question 1

State what is meant by a metal-aqua complex.

Answer 1

a complex formed when a transition metal is forms co-ordinate bonds to water ligands

Question 2

State the colour of the [Fe(H₂O)₆]²⁺ ion in solution.

Answer 2

green sol

Question 3

State the colour of the [Cu(H₂O)₆]²⁺ ion in solution.

Answer 3

blue

Question 4

State the colour of the [Fe(H₂O)₆]³⁺ ion in solution.

Answer 4

yellow sol

Question 5

State the colour of the [Al(H₂O)₆]³⁺ ion in solution.

Answer 5

colourless solution

Question 6

Explain why a 3+ metal aqua ion is more acidic than a 2+ one.

Answer 6

→ higher charge density so greater polarising power
→ therefore attracts water molecule more strongly & weakens O-H bond
→ breaking more easily & releasing H+ ions

Question 7

State the colour and formula of the [Fe(H₂O)₆]²⁺ ion in NaOH.

Answer 7

Fe(H₂O)₄(OH)₂
green ppt

Question 8

State the colour and formula of the [Cu(H₂O)₆]²⁺ ion in NaOH.

Answer 8

Cu(H₂O)₄(OH)₂
blue ppt

Question 9

State the colour and formula of the [Fe(H₂O)₆]³⁺ ion in NaOH.

Answer 9

Fe(H₂O)₃(OH)₃
brown ppt

Question 10

State the colour and formula of the [Al(H₂O)₆]³⁺ ion in NaOH.

Answer 10

Al(H₂O)₃(OH)₃
white ppt

Question 11

State the colour and formula of the [Al(H₂O)₆]³⁺ ion in excess NaOH.

Answer 11

[Al(OH)₄]⁻
colourless solution

Question 12

State the colour and formula of the [Fe(H₂O)₆]²⁺ ion in NH₃.

Answer 12

Fe(H₂O)₄(OH)₂
green ppt

Question 13

State the colour and formula of the [Fe(H₂O)₆]³⁺ ion in NH₃.

Answer 13

Fe(H₂O)₃(OH)₃
brown ppt

Question 14

State the colour and formula of the [Cu(H₂O)₆]²⁺ ion in NH₃.

Answer 14

Cu(H₂O)₄(OH)₂
blue ppt

Question 15

State the colour and formula of the [Al(H₂O)₆]³⁺ ion in NH₃.

Answer 15

Al(H₂O)₃(OH)₃
white ppt

Question 16

State the colour and formula of the [Cu(H₂O)₆]²⁺ ion in excess NH₃.

Answer 16

[Cu(H₂O)₂(NH₃)₄]²⁺
deep blue solution

Question 17

State the colour and formula of the [Cu(H₂O)₆]²⁺ ion in concentrated HCl.

Answer 17

[CuCl₄]²⁻
green-yellow solution

Question 18

What do X²⁺ ions form when reacted with carbonate solution?

Answer 18

XCO₃

Question 19

What do X³⁺ ions form when reacted with carbonate solution?

Answer 19

X(OH)₃(H₂O)₃ + 3CO₂ + 3H₂O

Question 20

State the colour and formula of the [Cu(H₂O)₆]²⁺ ion when it reacts with sodium carbonate.

Answer 20

CuCO₃
green-blue ppt

Question 21

Describe the appearance of CoCO3

Answer 21

purple solid

Question 22

State colour and appearance of [Fe(H₂O)₆]³ with Na2CO3

Answer 22

Fe(H₂O)₃(OH)₃
brown ppt

Question 23

Reactions with sodium hydroxide

Answer 23

All four metals will ppt, only aluminium hydroxide will dissolve in excess- due to amphoteric

Question 24

Reaction with ammonia

Answer 24

All four metal will form ppt, only copper hydroxide will dissolve in excess due to ligand sub

Question 25

Reactions with sodium carbonate

Answer 25

All four metals will ppt, Sol with Al3+ or Fe3+ bubble as CO2, Fe3+ will give off gas but Fe2+ wont