Reaction of aqueous ions

Question 1

Define ligand

Answer 1

Ion with a lone pair of electrons which can form a co-ordinate bond with a metal ion

Question 2

What is the formula and colour of the iron (II) aqueous ion?

Answer 2

[Fe(H2O)6]2+
green solution

Question 3

What is the formula and colour of the copper (II) aqueous ion?

Answer 3

[Cu(H2O)6]2+
blue solution

Question 4

What is the formula and colour of the iron (III) aqueous ion?

Answer 4

[Fe(H2O)6]3+
purple solution

Question 5

What is the formula and colour of the aluminium (III) aqueous ion?

Answer 5

[Al(H2O)6]3+
colourless solution

Question 6

Why are the 3+ ions more acidic than the 2+ ions? (6)

Answer 6

• Fe3+ has a higher charge and is smaller than 2+
• Fe3+ is more polarising
• Fe3+ strongly attracts the lone pair on the oxygen of water ligands
• This weakens the strength go the O-H bond
• Fe(III) complex more easily releases H+ ions making the solution acidic
• Fe(II) complex doesn’t release H+ ions

Question 7

What is the formula and colour of the iron (II) aqueous ion with NaOH?

Answer 7

Fe(H2O)4(OH)2
Green ppt goes brown with standing

Question 8

What is the formula and colour of the iron (II) aqueous ion with excess NaOH?

Answer 8

Fe(H2O)4(OH)2
Green ppt
No further change

Question 9

What is the formula and colour of the iron (II) aqueous ion with NH3?

Answer 9

Fe(H2O)4(OH)2
Green ppt goes brown with standing

Question 10

What is the formula and colour of the iron (II) aqueous ion with excess NH3?

Answer 10

Fe(H2O)4(OH)2
Green ppt
No further change

Question 11

What is the formula and colour of the iron (II) aqueous ion with Na2CO3?

Answer 11

FeCO3
Green ppt

Question 12

What is the formula and colour of the copper (II) aqueous ion with NaOH?

Answer 12

Cu(H2O)4(OH)2
Blue ppt

Question 13

What is the formula and colour of the copper (II) aqueous ion with excess NaOH?

Answer 13

Cu(H2O)4(OH)2
Blue ppt
No further change

Question 14

What is the formula and colour of the copper (II) aqueous ion with NH3?

Answer 14

Cu(H2O)4(OH)2
Blue ppt

Question 15

What is the formula and colour of the copper (II) aqueous ion with excess NH3?

Answer 15

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

Question 16

What is the formula and colour of the copper (II) aqueous ion with Na2CO3?

Answer 16

CuCO3
Blue-green ppt

Question 17

What is the formula and colour of the iron (III) aqueous ion with NaOH?

Answer 17

Fe(H2O)3(OH)3
Brown ppt

Question 18

What is the formula and colour of the iron (III) aqueous ion with excess NaOH?

Answer 18

Fe(H2O)3(OH)3
Brown ppt
No further change

Question 19

What is the formula and colour of the iron (III) aqueous ion with NH3?

Answer 19

Fe(H2O)3(OH)3
Brown ppt

Question 20

What is the formula and colour of the iron (III) aqueous ion with excess NH3?

Answer 20

Fe(H2O)3(OH)3
Brown ppt

Question 21

What is the formula and colour of the iron (III) aqueous ion with Na2CO3?

Answer 21

Fe(H2O)3(OH)3
Brown ppt
Effervescence

Question 22

What is the formula and colour of the aluminium (III) aqueous ion with NaOH?

Answer 22

Al(OH)3(H2O)3
White ppt

Question 23

What is the formula and colour of the aluminium (III) aqueous ion with excess NaOH?

Answer 23

[Al(H2O)2(OH)4]-
Colourless solution

Question 24

What is the formula and colour of the aluminium (III) aqueous ion with NH3?

Answer 24

Al(H2O)3(OH)3
White ppt

Question 25

What is the formula and colour of the aluminium (III) aqueous ion with excess NH3?

Answer 25

Al(H2O)3(OH)3
White ppt
No further change

Question 26

What is the formula and colour of the aluminium (III) aqueous ion with Na2CO3?

Answer 26

Al(H2O)3(OH)3
White ppt
CO2 gas

Question 27

What is the formula and colour of the copper (II) aqueous ion with Hal?

Answer 27

[CuCl4]2-
Yellow solution