Ligand Substitution

What colour is [Cu(H2O)6]+2 aq solution?

Pale blue

Give the equation when dilute ammonia reacts with [Cu(H2O)6]+2 & colour produced?

[Cu(H2O)6]+2 + 2NH3 → [Cu(NH3)2(H2O)4]+2 + 2H2O

• Pale blue solution produced

Give the equation when concentrated / excess ammonia is reacted with [Cu(H2O)6]+2 & colour produced?

[Cu(H2O)6]+2 +4NH3 → [Cu(NH3)4(H2O)2}+2 + 4H2O

• Produces dark blue solution

Why doesn’t the charge change when ammonia is added to [Cu(H2O)6]+2?

Ammonia is a neutral ligand so won’t change charge

Give the equation when [Cu(H2O)6]+2 reacts with chloride ions, colour produced and change in shape?

[Cu(H2O)6]+2 + 4Cl-1 ⇌ [CuCl4]-2 + 6H2O

• Yellow / Green solution produced (looks green as its the equilibrium between blue solution and yellow)

• Changed to tetrahedral shape with a coordination number of 4

What is the colour of [Cr(H2O)6]+3 aq?

Dark green

Give the equation when dilute ammonia reacs with [Cr(H2O)6]+3?

[Cr(H2O)6]+3 + 3NH3 → [Cr(NH3)3(H2O)3]3+ + 3H2O

Give the equation when concentrated / excess ammonia is added to [Cr(H2O)6]+3 & give colour produced?

[Cr(H2O)6]+3 + 6NH3 → [Cr(NH3)6]+3 + 6H2O

• Purple solution

What is the product formed when chloride ions react with [Cr(H2O)6]+3?

[CrCl4]-1

What is a precipitation reaction?

Reaction from aqueous to solid

Give the equation when [Cu(H2O)6]+2 reacts with hydroxide ions & colour produced:

[Cu(H2O)6]+2 + 2OH^-1 → [Cu(OH)2(H2O)4] + 2H2O

• Blue precipitate

Give the equation when [Cu(H2O)6]+2 reacts with dilute ammonia to produce a PRECIPITATE, why it happens & colour produced:

[Cu(H2O)6]+2 + 2NH3 → [Cu(OH)2(H2O)4] + 2NH4+1

(x2 of the H from the H2O taken out is given to ammonia to make NH4+1

Give the equation when EXCESS ammonia is added to [Cu(H2O)6]+2 to form a PRECIPITATE, why it happens, colour?

[Cu(H2O)6]+2 + 4NH3 → [Cu(NH3)4(H2O)2]2+ + 2H2O + 2OH -1

(ammonia is strong enough to do full substitution)

• Dark blue precipitate

What the equation for the product formed when Iron +2 ions react with OH-1 or dilute NH3 & give colour produced?

[Fe(OH)2(H2O)4]

• Green precipitate

Give the formula of the product formed when Mn+2 reacts with OH-1 or dilute NH3 & colour produced?

[Mn(OH)2(H2O)4]

• Pink ppt

Give the formula of the product formed when Iron+3 reacts with OH-1 or dilute NH3 & colour produced:

[Fe(OH)3(H2O)3]

• Brown / orange ppt

Give the formula of the product formed when Cr3+ reacts with OH-1 or dilute NH3 & colour produced:

[Cr(OH)3(H2O)3]

• Green ppt

What does haemoglobin bind to?

Protein, H2O, O2

What does haemoglobin NOT carry & what replaces it?

CO2 as it will only carry Carbon monoxide when it bonds where the O2 should go making a strong coordinate bond so O2 can not remove CO easily