Metal Aqua Ions

Question 1

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

Answer 1

Green

Question 2

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

Answer 2

Blue

Question 3

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

Answer 3

Colourless

Question 4

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

Answer 4

Yellow

Question 5

What are metal salts typically represented as?

Answer 5

Anhydrous ionic solids

Question 6

What is the definition for a brønsted lowery acid?

Answer 6

Proton donor

Question 7

What is the definition for a brønsted lowery base?

Answer 7

Proton acceptor

Question 8

What are metal aqua ion complexes also known as?

Answer 8

Weak acids

Question 9

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

Answer 9

Water breaks down to become a H+ donor. This happens more in 3+ aqua ions

Question 10

What is the general equation for 2+ complexes when added to water?

Answer 10

[metal(water)6]2+ + water —> [metal(water) 5 (OH)]+ + H3O+

Question 11

What is the general equation for 2+ complexes when added to water?

Answer 11

[metal(water)6]3+ + water —> [metal(water) 5 (OH)]2+ + H3O+

Question 12

State the chemical chain of reactions when sodium hydroxide is added to [Al(H2O)6]3+ drop wise, in excess and standing in air….

Answer 12

Drop wise: colourless solution to white ppt
Excess: white ppt to colourless solution
In air: no change

Question 13

State the chemical chain of reactions when sodium hydroxide is added to [Fe(H2O)6]3+ drop wise, in excess and standing in air….

Answer 13

Drop wise: yellow solution to brown ppt
Excess: no change
In air: no change

Question 14

State the chemical chain of reactions when sodium hydroxide is added to [Cu(H2O)6]2+drop wise, in excess and standing in air….

Answer 14

Drop wise: blue solution to blue ppt
Excess no change
In air: no change

Question 15

State the chemical chain of reactions when sodium hydroxide is added to [Fe(H2O)6]2+drop wise, in excess and standing in air….

Answer 15

Drop wise: green solution to green ppt
Excess no change
In air green ppt oxidises to brown ppt

Question 16

What is the general equation for 2+ complexes when sodium hydroxide is added?

Answer 16

[Metal(water)6]2+ (aq) + 2OH- —-> M(H2O)4(OH)2 (s) + 2 water

Question 17

What is the general equation for 3+complexes when sodium hydroxide is added?

Answer 17

[Metal(water)6]3+ (aq) + 3OH- —-> M(H2O)3(OH)3 (s) + 3 water

Question 18

What can be added to reverse the reaction between metal aqua ions with sodium hydroxide?

Answer 18

Hydrochloric acid

Question 19

How do metal hydroxides precipitates act?

Answer 19

As bases

Question 20

What does amphoteric mean?

Answer 20

Reacts with both acids and alkalis

Question 21

Give 2 examples of transition metals that are amphoteric

Answer 21

Al3+

Cr3+

Question 22

Give the general equation equation for metal aqua ion reactions with ammonia solution

Answer 22

[metal(water)6]2+/3+ + 2/3NH3 —> M(H2O)3/4(OH)2/3 + 2/3 NH4+

Question 23

When ammonia is added to metal aqua ions what does it act as?

Answer 23

Brønsted lowery base

Question 24

Give the formula of the anode complex when an excess/ conc ammonia is added to copper hexa aqua ion

Answer 24

[copper(NH3)4(H2O)2]2+

Question 25

Give the colour changes when dilute ammonia is added drop wise, in excess and on standing in air to aluminium hexa aqua ion

Answer 25

Drop wise colourless to white ppt Excess no further change Standing no further change

Question 26

Give the colour changes when dilute ammonia is added drop wise, in excess and on standing in air to iron (iii) hexa aqua ion

Answer 26

Drop wise yellow solution to brown ppt | Excess and standing have no further change

Question 27

Give the colour changes when dilute ammonia is added drop wise, in excess and on standing in air to copper hexa aqua ion

Answer 27

Drop wise blue solution to blue ppt Excess light blue ppt to deep blue ppt In air no further change

Question 28

Give the colour changes when dilute ammonia is added drop wise, in excess and on standing in air to iron (Ii) hexa aqua ion

Answer 28

Drop wise green solution to green ppt Excess no change In air brown ppt

Question 29

Give the general equation for the reaction of a 2+ metal aqua ion with sodium carbonate

Answer 29

[M(H2O)6]2+ + CO3- —> MCO3 + 6 water