Metal Aqua Ions

Question 1

what colour is [Cu(H2O)6]²+

Answer 1

blue

Question 2

what colour is [Co(H2O)6]²+

Answer 2

pink

Question 3

what colour is [Fe(H2O)6]²+

Answer 3

green

Question 4

what colour is [V(H2O)6]3+

Answer 4

green

Question 5

what colour is [V(H2O)6]3+

Answer 5

violet

Question 6

what colour is [Cr(H2O)6]3+

Answer 6

violet

Question 7

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

Answer 7

pale violet

Question 8

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

Answer 8

colourless

Question 9

write the reaction for: NaOH(aq) + [Fe(H2O)6]²+
(dropwise)
- what is the colour / state change?

Answer 9

[Fe(H2O)6]2+ + 2OH- → Fe(H2O)4(OH)2 + 2H2O (hydrolysis)
- green solution to green precipitate

Question 10

NaOH(aq) + [Fe(H2O)6]²+
(excess NaOH)

Answer 10

no further reaction, but darkens over time on oxidation to [Fe(H2O)3(OH)3]

Question 11

write the reaction for: NaOH(aq) + [Cu(H2O)6]²+
(dropwise)
- what is the colour / state change?

Answer 11

[Cu(H2O)6]2+ + 2OH- → [Cu(H2O)4(OH)2] + 2H2O (hydrolysis)
- blue solution to blue precipitate

Question 12

NaOH(aq) + [Cu(H2O)6]²+
(excess NaOH)

Answer 12

no further reaction

Question 13

write the reation for: NaOH(aq) + [Fe(H2O)6]3+ (dropwise)
- what is the colour / state change?

Answer 13

[Fe(H2O)6]3+ + 3OH- → [Fe(H2O)3(OH)3] + 3H2O (hydrolysis)
- pale violet solution to brown precipitate

Question 14

NaOH(aq) + [Fe(H2O)6]3+
(excess NaOH)

Answer 14

no further reaction

Question 15

write the reaction for: NaOH(aq) + [Al(H2O)6]3+ (dropwise)
- what is the colour / state change?

Answer 15

[Al(H2O)6]3+ + 3OH- → [Al(H2O)3(OH)3] + 3H2O (hydrolysis)
- colourless solution to white precipitate

Question 16

NaOH(aq) + [Al(H2O)6]3+
(excess NaOH)
- what is the colour / state change?

Answer 16

[Al(H2O)3(OH)3] + OH- → [Al(H2O)2(OH)4]- + H2O (hydrolysis)
- white precipitate to colourless solution

Question 17

write the reaction for: NH3(aq) + [Fe(H2O)6]²+ (dropwise)
- what is the colour / state change?

Answer 17

[Fe(H2O)6]2+ + 2NH3 → [Fe(H2O)4(OH)2] + 2NH4+ (hydrolysis)
- green solution to green precipitate

Question 18

NH3(aq) + [Fe(H2O)6]²+
(excess NH3)

Answer 18

no further reaction, but darkens over time on oxidation to [Fe(H2O)3(OH)3]

Question 19

write the reaction for: NH3(aq) + [Cu(H2O)6]²+ (dropwise)
- what is the colour / state change?

Answer 19

[Cu(H2O)6]2+ + 2NH3 → [Cu(H2O)4(OH)2] + 2NH4+ (hydrolysis)
- blue solution to blue precipitate

Question 20

NH3(aq) + [Cu(H2O)6]²+
(excess NH3)
- what is the colour change?

Answer 20

[Cu(H2O)4(OH)2] + 4NH3 → [Cu(H2O)2(NH3)4]2+ + 2H2O + 2OH- (substitution)
- blue precipitate to (dark) blue solution

Question 21

write the reaction for: NH3(aq) + [Fe(H2O)6]3+ (dropwise)
- what is the colour change?

Answer 21

[Fe(H2O)6]3+ + 3NH3 → [Fe(H2O)3(OH)3] + 3NH4+ (hydrolysis)
- pale violet solution to brown precipitate

Question 22

NH3(aq) + [Fe(H2O)6]3+ (excess reaction)

Answer 22

no further reaction

Question 23

write the reaction for: NH3(aq) + [Al(H2O)6]3+ (dropwise)
- what is the colour / state change?

Answer 23

[Al(H2O)6]3+ + 3NH3 → [Al(H2O)3(OH)3] + 3NH4+ (hydrolysis)
- colourless solution to white precipitate

Question 24

NH3(aq) + [Al(H2O)6]3+
(excess NH3)

Answer 24

no further reaction

Question 25

write the reaction for: CO3²-(aq) + [Fe(H2O)6]²+ (dropwise) - what is the colour /state change?

Answer 25

[Fe(H2O)6]2+ + CO32- → FeCO3 + 6H2O (precipitation) - green solution to green precipitate

Question 26

write the reaction for: CO3²-(aq) + [Cu(H2O)6]²+ (dropwise) - what is the colour / state change?

Answer 26

[Cu(H2O)6]2+ + CO32- → CuCO3 + 6H2O (precipitation) - blue solution to blue precipitate

Question 27

write the reaction for: CO3²-(aq) + [Fe(H2O)6]3+ (dropwise) - what is the colour / state change?

Answer 27

2 [Fe(H2O)6]3+ + 3CO32- → 2[Fe(H2O)3(OH)3] + 3H2O + 3CO2 (hydrolysis) - pale violet solution to brown precipitate

Question 28

write the reaction for: CO3²-(aq) + [Al(H2O)6]3+ (dropwise) - what is the colour / state change?

Answer 28

2[Al(H2O)6]3+ + 3CO32- → 2[Al(H2O)3(OH)3] + 3H2O + 3CO2 (hydrolysis) - colourless solution to white precipitate