Exam like qs

Why are 3+ ions more acidic than ethanoic acid?
They are smaller and are more strongly polarising so weakens bonds between O-H in water ligands
What is chelation?
The formation of complexes with multidentate ligands
Copper metal can be extracted from a dilute aqueous solution containing Cu2+ ions using scrap iron.
What is the equation and colour change?
What is the formula of the complex giving pink colour in CoCl2?
[Co(H2O)6]2+
What is the role of H2O2 in the reaction with [Co(NH3)6]2+?
Oxidising agent
What is formed when excess H2NCH2CH2NH2 is added to [Co(NH3)6]2+?
[Co(NH3)6]2+ + 3H2NCH2CH2NH2 -> [Co(H2NCH2CH2NH2)3]2+ + 6NH3
Why is [Co(H2NCH2CH2NH2)3]2+ more stable than [Co(NH3)6]2+?

Entropy/disorder increases for [Co(H2NCH2CH2NH2)3]2+

Four molecules form seven molecules.

Why does [Co(Cl)4]2- have a different coordination number to [Co(H2O)6]2+?
Cl- ions are larger so only four can fit around the transition metal ion
What reagent is added to [Co(H2O)6]2+ to form a complex that can be oxidised by H2O2 to form [Co(NH3)6]3+? What are the reactions and observations?
Conc. NH3
[Co(H2O)6]2+ + NH3 -> [Co(NH3)6]2+
Pink solution -> pale brown solution
With H2O2:
[Co(NH3)6]2+ -> [Co(NH3)6]3+
Pale brown solution -> darker brown solution
What features of transition metals allow them to have catalytic properties, form complex ions and form coloured solutions?
They have incomplete d orbitals
Transition metals have catalytic properties, form complex ions and form coloured solutions. What is the fourth characteristic?
Variable oxidation state
What is an example of a linear complex?
[H3N-Ag-NH3]+
[Cl-Ag-Cl]–
Cl-Be-Cl
What is an example of a square planar complex?
A cis platin drawn out as square planar
What is an example of a tetrahedral complex?
[Co(Cl)4]2-
[Cu(Cl)4]2-
What is the overall equation for the contact process?
SO2 + 1/2O2 -> SO3
What is the meaning of heterozygous when applied to a catalyst?
The catalyst is in a different state to the reactants
What are the two equations of the Contact Process demonstrating how vanadium(V) oxide acts as a catalyst?

V2O5 + SO2 -> V2O4 + SO3

V2O4 + 1/2O2 -> V2O5

What can be done to a catalyst to maximise ifs efficiency?
Finely divided to maximise surface area
What is the meaning of multidentate?
Forms more than one coordinate bond with a central transition metal ion
When cobalt(II) is coordinated to a porphyrin ring (it forms 4 coordinate bonds), a cyanide ion (CN-) and another unidentate ligand, what is its coordination number?
6
When cobalt(II) is coordinated to a porphyrin ring, a cyanide ion (CN-) and another unidentate ligand, why is it not toxic even though the cyanide ion is very toxic?
The cyanide ion is very strongly bound to cobalt

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