Reactions of ions in aqueous solutions

Question 1

State what you would observe when NaOH is added to the aqueous ion of Fe (II)

Answer 1

Green ppt formed which goes brown when left standing in air

Question 2

State what you would observe when NaOH is added to the aqueous ion of Cu (II)

Answer 2

(Light) blue ppt formed

Question 3

State what you would observe when NaOH is added to the aqueous ion of Fe (III)

Answer 3

Brown ppt formed (may look orange-brown)

Question 4

State what you would observe when NaOH is added to the aqueous ion of Al (III)

Answer 4

White ppt formed

Question 5

State what you would observe when NaOH is added to the aqueous ion of Co (II)

Answer 5

(Dark) blue ppt formed

Question 6

What colour is the solution of the aqueous ion of Fe (II)?

Answer 6

Green

Question 7

What colour is the solution of the aqueous ion of Fe (III)?

Answer 7

Purple (may look yellow-brown)

Question 8

What colour is the solution of the aqueous ion of Al (III)?

Answer 8

Colourless

Question 9

What colour is the solution of the aqueous ion of Cu (II)?

Answer 9

Blue

Question 10

What colour is the solution of the aqueous ion of Co (II)?

Answer 10

Pink

Question 11

The aqueous ion of Fe (III) is purple. However, the solution sometimes appears yellow-brown. Why is this?

Answer 11

Some [Fe(H2O)5(OH)2]2+ has been formed

Question 12

NaOH is added to Fe (I) and a green ppt is formed. Excess NaOH is then added. What will be observed (if anything)?

Answer 12

No further change

Question 13

NaOH is added to Cu (II) and a blue ppt is formed. Excess NaOH is then added. What will be observed (if anything)?

Answer 13

No further change

Question 14

NaOH is added to Fe (III) and a brown ppt is formed. Excess NaOH is then added. What will be observed (if anything)?

Answer 14

No further change

Question 15

NaOH is added to Al (III) and a white ppt is formed. Excess NaOH is then added. What will be observed (if anything)?

Answer 15

Colourless soln. formed (but different complex from original aq ion)

Question 16

State what you would observe when NH3 is added to the aqueous ion of Fe (II)

Answer 16

Green ppt formed which goes brown on standing in air

Question 17

State what you would observe when NH3 is added to the aqueous ion of Cu (II)

Answer 17

(Light) blue ppt formed

Question 18

State what you would observe when NH3 is added to the aqueous ion of Fe (III)

Answer 18

Brown ppt (may look orange-brown)

Question 19

State what you would observe when NH3 is added to the aqueous ion of Al (III)

Answer 19

White ppt formed

Question 20

State what you would observe when excess NH3 is added to the aqueous ion of Co (II)

Answer 20

Pale brown soln. formed

Question 21

NH3 is added to Fe (II) and a green ppt is formed. Excess NH3 is then added. What will be observed (if anything)?

Answer 21

No further change

Question 22

NH3 is added to Cu (II) and a blue ppt is formed. Excess NH3 is then added. What will be observed (if anything)?

Answer 22

Deep blue soln. formed

Question 23

NH3 is added to Fe (III) and a brown ppt is formed. Excess NH3 is then added. What will be observed (if anything)?

Answer 23

No further change

Question 24

NH3 is added to Al (III) and a white ppt is formed. Excess NH3 is then added. What will be observed (if anything)?

Answer 24

No further change

Question 25

State what you would observe when Na2CO3 is added to the aqueous ion of Fe (II)

Answer 25

(Light) green ppt formed

Question 26

State what you would observe when Na2CO3 is added to the aqueous ion of Cu(II)

Answer 26

Blue-green ppt formed

Question 27

State what you would observe when Na2CO3 is added to the aqueous ion of Fe (III)

Answer 27

Brown ppt formed (may look orange brown) CO2 gas released

Question 28

State what you would observe when Na2CO3 is added to the aqueous ion of Al (III)

Answer 28

White ppt CO2 gas evolved

Question 29

State what you would observe when Na2CO3 is added to the aqueous ion of Co (II)

Answer 29

Purple ppt formed

Question 30

State what you would observe when HCl is added to the aqueous ion of Cu (II)

Answer 30

Yellow soln. formed (may look green)

Question 31

State what you would observe when HCl is added to the aqueous ion of Co (II)

Answer 31

Blue soln. formed

Question 32

A soln. of ammonium vanadate (V) (NH4VO3) is reduced by zinc under acidic conditions. A yellow soln. is formed. What is the oxidation state of vanadium?

Answer 32

V (V)

Question 33

A soln. of ammonium vanadate (V) (NH4VO3) is reduced by zinc under acidic conditions. A blue soln. is formed. What is the oxidation state of vanadium?

Answer 33

4

Question 34

A soln. of ammonium vanadate (V) (NH4VO3) is reduced by zinc under acidic conditions. A green soln. is formed. What is the oxidation state of vanadium?

Answer 34

V (III)

Question 35

A soln. of ammonium vanadate (V) (NH4VO3) is reduced by zinc under acidic conditions. A violet/purple soln. is formed. What is the oxidation state of vanadium?

Answer 35

V (II)

Question 36

V (II) forms what colour solution?

Answer 36

Violet/purple

Question 37

V (III) forms what colour solution?

Answer 37

Green

Question 38

V (IV) forms what colour solution?

Answer 38

Blue

Question 39

V (V) forms what colour solution?

Answer 39

Yellow

Question 40

Which is more acidic of M3+ and M2+ and why? (M=metal)

Answer 40

M3+ It has a greater polarising power as it is smaller and has a greater charge than M2+ This means the O-H bond breaks more easily and so more H+ are released