Transition Metal Colours

Question 1

V^2+

Answer 1

Lavender

Question 2

V^3+

Answer 2

Green

Question 3

VO^2+

Answer 3

Blue

Question 4

VO2 ^+

Answer 4

Yellow

Question 5

VO3 -

Answer 5

Colourless

Question 6

NH4VO3

Answer 6

Colourless solid

Yellow in solution

Question 7

Cr 2+

Answer 7

Blue

Question 8

Cr^3+

Answer 8

Green

Question 9

CrO4 ^2-

Answer 9

Yellow

Question 10

Cr2O7 ^2-

Answer 10

Orange

Question 11

Fe^2+ + NaOH

Answer 11

Green precipitate
Goes brown on exposure to air as oxidised to iron (III)

Excess NaOH
insoluble

Question 12

Fe3+ plus NaOH

Answer 12

Red brown ppt

Insoluble In NaOH

Question 13

Co 2+ NaOH

Answer 13

Blue ppt

Turns pink on standing as it loses water

Insoluble In excess

Question 14

Cr3+ NaOH

Answer 14

Green ppt

Green solution in excess

Question 15

Cu 2+ NaOH

Answer 15

Blue ppt

Insoluble excess

Question 16

Fe 2+ aq

Answer 16

Pale Green

Question 17

Fe 3+ aq

Answer 17

Yellow

Question 18

Co 2+ aq

Answer 18

Pink

Question 19

Mn 2+ aq

Answer 19

Pale pink

Question 20

Cu 2+ aq

Answer 20

Blue green

Question 21

Cr 3+ ammonia

Answer 21

Green ppt

In excess
Dissolved slightly to form green solution very slowly

Question 22

Fe 2+ ammonia

Answer 22

Green ppt
Darken as oxidised in air

Insoluable In excess

Question 23

fe3+ in ammonia

Answer 23

Red brown ppt

Insoluable In excess

Question 24

Co2+ ammonia

Answer 24

Blue ppt

Dissolved to form brown solution in excess

Question 25

Cu 2+ ammonia

Answer 25

Blue ppt

Deep blue solution in excess

Question 26

Copper with chlorine ligand

Answer 26

Yellow solution

Question 27

Cobalt with chlorine ligand

Answer 27

Blue solution

Question 28

Iron catalyst in iodide thiosulphate reaction

Answer 28

S2O8 2- + 2Fe2+ -> 2SO4 2- + 2Fe3+

2Fe3+ + 2I- -> 2Fe2+ + I2

Question 29

Autocatalysis

Answer 29

2MnO4 - + 16H+ + 5C2O4^2- -> 2Mn 2+ + 10CO2 + 8H20