Complex Titrations Flashcards
(46 cards)
These are class of reactions that deal with complex formations
Complexation methods
multiple parts of ligand an donate electron
Chelate
One part of ligand can donate electron
Complex
It is highly colored dyes that are weak reducing or oxidizing agents that can be oxidized or
reduced
Complexation
it is an unstable complex
Group 1A metals
It is more stable
Divalent or Trivalent
Cheating Agent/Complexing Agent/ Complexone
Titrant
Excess e is a pair of
dentates
Metals
Analyte
if a ligand binds to a metal ionthat has only one atom
monodentate
the ability of a ligand to form more stable metal complex if there are more molecules/atoms in a ligand.
Chelated effect
has a sharper cheating effect than monodentates forming a much more stable complex
Multidentate ligands
give more stable complexes than hexadentates (EDTA), however, EDTA has the
widest general application in the analysis because of its powerful complexing action and commercial availability.
Octadentates (DTPA)
is he dissociation constant of a chemical equiatin
pKn or Kn
It implies that complex metric Titration requires __ _______ at which metals are being analyzed
pH Control
The dissociation reaction of EDTA is??
Dependent on pH
The ____ H+ in a solution, the dissociation content (K) increases (pK decreases), making the reaction proceeds backwards
More
in EDTA titrations, the _________ _________ ___, forms complexes with metal ions
Unprotonated ligand Y^-4
For successful titrations with EDTA, the Kf (as log) of the complex formed must be greater than _
8
The ____ Kf of a complex, the ____ pH at which the Complexation Titration will form
More, Lower
what is the minimum pH at which complexes exist? Bi3+, Fe3+
1 - 3
at what minimum of pH at which complexes exist? Pb2+, Cu2+, Zn2+, Co2+, Ni2+, Mn2+, Fe2+, Al3+, Cd2+, Sn2+
4 - 6
at which minimum pH does Ca2+, Sr2+, Ba2+, Mg2+ complexes exist?
8 - 10
What are the factors that affect the stability of a complex?
Temperature
>8 pKn
Solvents
Dentate
Salt - decreasing stability
