2.6 Aqueous Ions

Question 1

What is the definition of a Lewis Acid?

Answer 1

Electron pair acceptor

Question 2

What is the definition of a Lewis Base?

Answer 2

Electron pair donator

Question 3

What acts as the Lewis base in a complex ion?

Answer 3

The ligands

Question 4

What is the equation of a 2+ metal aqua ion at equilibria?

Answer 4

[M(H2O)6]2+ + H2O >< [M(h2O)5(OH)]+ + H3O+

Question 5

Why are 3+ ions more acidic than 2+ ion metal aqua ions?

Answer 5

• Higher charge density
• Greater polarising power
• More strongly attracts h2O
• Weakens O-H bond more easily so more H+ released

Question 6

What colour is [CuCl4]2-?

Answer 6

Green solution

Question 7

What colour is [FeCl4]2-?

Answer 7

Yellow

Question 8

How are chloride complex ions changed to hexa aqua ions?

Answer 8

Excess water added

Question 9

What colour is [Cu(H2O)6]2+?

Answer 9

Blue solution

Question 10

What colour is [Fe(H2O)6]2+?

Answer 10

Green solution

Question 11

What does adding a few drops of NH3 to [Fe(H2O)6]2+ form?

Answer 11

[Fe(OH)2(H2O)4
Green precipitate

Question 12

If [Fe(OH)2(H2O)4] is exposed to air what forms?

Answer 12

Brown precipitate
Fe(OH)3(H2O)3

Question 13

What colour precipitate is CuCO3?

Answer 13

Blue precipitate

Question 14

What colour is [Al(H2O)6] 3+?

Answer 14

Colourless

Question 15

What colour is [Fe(H2O)6]3+?

Answer 15

Yellow

Question 16

How is Al(OH)3(H2O)3 formed from [Al(H2O)6]?

Answer 16

Few drops of NH3/ OH-

Question 17

What is formed when [Al(H2O)6]3+ reacts with CO3 2-?

Answer 17

White precipitate
Al(OH)3(h2O)3
Bubbles of Co2

Question 18

What is formed when [Fe(H2O)6] 3+ reacts with CO2

Answer 18

Fe(OH)3(H2O)3
Brown precipitate
Bubbles of CO2