Colours Of Transition Elements

Question 1

[Cu(H20)6]2+

Answer 1

Pale blue

Question 2

Cu(OH)2 (s)

Answer 2

Pale blue precipitate

Question 3

[Cu(NH3)4(H20)2]^2+

Answer 3

dark blue

Question 4

CuCl4^2-

Answer 4

yellow

Question 5

Cu^+

Answer 5

reduction of Cu^2+ with I^- white precipitate (CuI) and brown I2

Question 6

Cu^2+/Cu

Answer 6

disproportional of Cu^+ brown solid (Cu) and blue solution (CuSO4)

Question 7

CoCl4^2-

Answer 7

blue

Question 8

[Cr(H2O)6]^3+

Answer 8

pale purple but looks green due to impurities

Question 9

Cr(OH)3 (s)

Answer 9

dark green precipitate

Question 10

[Cr(NH3)6]^3+

Answer 10

Purple

Question 11

[Cr(OH)6]^3-

Answer 11

dark green

Question 12

Cr2O7^2-

Answer 12

orange

Question 13

CrO4^2-

Answer 13

yellow

Question 14

[Mn(H2O)6]^2+

Answer 14

Pale pink

Question 15

Mn(OH)2 (s)

Answer 15

pale brown precipitate

Question 16

[Fe(H2O)6]^2+

Answer 16

pale green

Question 17

Fe(OH)2 (s)

Answer 17

dark green precipitate

Question 18

[Fe(H2O)6]^3+

Answer 18

yellow

Question 19

Fe(OH)3 (s)

Answer 19

orange-brown precipitate

Question 20

MnO4^-/Fe^2+ —> Mn^2+/Fe^3+

Answer 20

purple (MnO4^-) to pale pink (Mn^2+)

Question 21

I^-/Fe^3+ —> I2/Fe^2+

Answer 21

orange brown (Fe^3+) to brown (I2)

Question 22

Cl- + anything

Answer 22

No reaction

Question 23

Br- + Cl2

Answer 23

Aqueous: yellow
Organic: orange

Question 24

I- + Cl2

Answer 24

Aqueous: orange/brown
Organic: purple

Question 25

I- + Br2

Answer 25

Aqueous: orange/brown Organic: purple

Question 26

Chlorine water aqueous and organic layers colours

Answer 26

Both colourless

Question 27

Bromine water aqueous and organic layers colours

Answer 27

Aqueous: yellow Organic: orange

Question 28

Iodine solution aqueous and organic layers colours

Answer 28

Aqueous: orange/brown Organic: purple