Transition metals

Question 1

What’s the ligand exchange reaction of Copper(II) sulphate and sodium hydroxide
and what’s the observation

Answer 1

[Cu(H2​O)6​]2+ + 2OH−→[Cu(H2​O)4​(OH)2​] + 2H2​O
Blue solution to blue precipitate

Question 2

What’s the ligand exchange reaction of Copper(II) sulphate and ammonia
and what’s the observation

Answer 2

[Cu(H2​O)6​]2+ + 2NH3→[Cu(H2​O)4​(OH)2​] + 2NH4+
Blue solution to blue precipitate

Question 3

What’s the ligand exchange reaction of Copper(II) sulphate and excess ammonia - (product of non excess carries over)
and what’s the observation

Answer 3

[Cu(H2​O)4(OH)2​] + 4NH3→[Cu(NH3)4​(H2O)2​] + 2H2​O + 2OH-
Blue ppt to deep blue solution

Question 4

What’s the ligand exchange reaction of Copper(II) sulphate and conc HCl
and what’s the observation- 3 piece

Answer 4

[Cu(H2​O)6​]2+ + 4Cl- →[CuCl4​] + 6H20
Blue to Green to Yellow

Question 5

Hexaaquacolbalt(II) + NaOH(aq) = ?
and what observations can be made

Answer 5

[Co(H2​O)6​]2+ + 2OH- →[Co(H2O)4(OH)2​] + 2H20
Pink solution to Blue ppt

Question 6

Hexaaquacolbalt(II) +Ammonia(aq) = ?
and what observations can be made

Answer 6

[Co(H2​O)6​]2+ + 2NH3- →[Co(H2O)4(OH)2​] + 2NH4+
Pink Sol to Blue ppt

Question 7

Hexaaquacolbalt(II) + EXCESS Ammonia(aq) = ? - (product carries over)
and what observations can be made

Answer 7

[Co(H2​O)4(OH)​]2+ + 6NH3- →[Co(NH3)6​] + 4H20 +2OH-
BLUE PPPR TO BROWN SOL

Question 8

Hexaaquacolbalt(II) +CONC HCl(aq) = ?
and what observations can be made

Answer 8

[Co(H2​O)6​]2+ + 4Cl- →[CoCl4​] + 6H20
Pink Sol to Blue Sol

Question 9

Hexaaquairon(II) + NaOH/NH3 = ?
and what observations

Answer 9

[Fe(H2O)6]2+ + 2OH-/2NH3 → [Fe(H2O)4(OH)2] + 2H2O/2NH4+
Pale green sol to Green ppt

Question 10

Hexaaquairon(III) + NaOH/NH3 = ?
and what observations

Answer 10

[Fe(H2O)6]3+ + 3OH-/3NH3 → [Fe(H2O)3(OH)3] + 3H2O/3NH4+
Yellow sol to Brown ppt (stinky)

Question 11

Hexaquachromium(III) + NaOH/NH3 = ?
and what observations

Answer 11

[Cr(H2O)6]3+ + 3OH-/3NH3 → [Cr(H2O)3(OH)3] + 3H2O/3NH4+
Violet sol to Green ppt

Question 12

Hexaquachromium(III) + EXCESS NaOH = ? - carry over
and what observations

Answer 12

[Cr(H2O)3(OH)3] + OH- → [Cr(OH)4(H2O)2]- + H20
Green ppt dissolves and forms green Sol

Question 13

Hexaquachromium(III) + EXCESS NH3 = ? - carry over
and what observations

Answer 13

[Cr(H2O)3(OH)3] + 6NH2 → [Cr(NH3)6]3+ + 3H20 + 3OH-
Green ppt to Violet Sol

Question 14

Hexaquachromium(III) + EXCESS CONC NaOH = ? - carry over
and what observations

Answer 14

[Cr(H2O)3(OH)3] + 2OH → [Cr(OH)6]3- +2H2O
Green PPt to Green Sol