5F - Transition elements - oxidation state & colours

Question 1

Solution of iron (II) ions

Answer 1

Fe²⁺_(aq) or [Fe(H₂O)₆]²⁺

Pale green solution

Question 2

Solution of iron (III) ions

Answer 2

Fe³⁺(aq) or [Fe(H₂O)₆]³⁺

Yellow solution

Question 3

Iron (II) hydroxide precipitaite

Answer 3

Fe(OH)₂

Pale green precipitate

Question 4

Iron (III) hydroxide precipitate

Answer 4

Fe(OH)₃

Orange / brown precipitate

Question 5

Solution of copper (II) ions

Answer 5

Cu²⁺_(aq) or [Cu(H₂O)₆]²⁺

Pale blue solution

Question 6

Solution of Tetraamminediaquacopper (II) ions

Answer 6

[Cu(NH₃)₄(H₂O)₂]²⁺

Dark blue solution

Question 7

Solution of Tetrachlorocuprate (II) ions

Answer 7

[CuCl₄]^-

Yellow solution

Question 8

Copper (II) hydroxide precipitate

Answer 8

Cu(OH)_2(s)

Pale blue precipitate

Question 9

Solution of Chromium (II) ions

Answer 9

Cr²⁺_(aq) or [Cr(H₂O)₆]²⁺

Blue solution

Question 10

Solution of Chromium (III) ions

Answer 10

Cr³⁺(aq) or [Cr(H₂O)₆]³⁺

Violet solution

Question 11

Solution of Pentaaquasulphatochromium (III) ions

Answer 11

[Cr(H₂O)₅SO₄]⁺ when H₂SO₄ is present

Green solution

Question 12

Solution of Hexaamminechromium (III) ions

Answer 12

[Cr(NH₃)₆]³⁺

Purple solution

Question 13

Solution of Hexahydroxochromium (III) ions

Answer 13

[Cr(H₂O)₆]^3-

Dark green solution

Question 14

Chromium (III) hydroxide precipitate

Answer 14

Cr(OH)_3(s)

Grey green precipitate

Question 15

Solution of Dichromate (VI) ions

Answer 15

Cr₂O₇^2-

Orange solution

Question 16

Solution of Manganese (II) ions

Answer 16

Mn²⁺

Pale pink solution

Question 17

Solution of Manganate (VII) ions

Answer 17

MnO₄^-

Purple solution

Question 18

Manganese (II) hydroxide precipitate

Answer 18

Mn)OH)₂

light brown precipitate