Complex Titrations Flashcards
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
mas maraming Solvents mas nagiging ____
stable
These are organic compounds which form colored complex ions with
metal ion (in high dilution).
Metallochromic indicators
Enumerate the qualities of a good in indicator
They react first with the metal ion being analyzed (before the metal is
complexed by EDTA)
Metallochromic indicators
What is the chemical reaction of standardization of 0.05 M Edetate Disodium
Complexation Reaction
What is the type of titration of standardization of 0.05 M Edetate Disodium
Direct
What is the RFIS of standardization of 0.05 M Edetate Disodium
Temperature
Drying
Distilled water
80 celsius
HCl
What is the indicator of standardization of 0.05 M Edetate Disodium
Hydroxynapthol Blue
What is the color transition of the endpoint of standardization of 0.05 M Edetate Disodium
Red to blue
What is the factor of standardization of 0.05 M Edetate Disodium
1
Zinc sulfate is commonly used as
_________ _______in residual complexometric
titrations such as in the assay of Al3+ and
Bi3+ compounds
Backtitrant
standard solution must be stored in a ______ ______
Amber bottle
What is chemical reaction in standardization of 0.05 M Zinc Sulfate
Complexometric Titration
What is type of titration in standardization of 0.05 M Zinc Sulfate
Direct titration
What is the analyte in standardization of 0.05 M Zinc Sulfate
Na2EDTA Disodium EDTA
What is pH condition in standardization of 0.05 M Zinc Sulfate
4.6
What is the buffer in standardization of 0.05 M Zinc Sulfate
Acetic acid-ammonium acetate
What is the indicator in standardization of 0.05 M Zinc Sulfate
Dithiozone
What is color transition at end point in standardization of 0.05 M Zinc Sulfate
Green to rose-pink
Factors that affect EDTA titration
Proper pH condition
Attainment of endpoint
Temperature
Amount of Metallochromic indicators
What are the most common metallochromic indicators
Dithiozone
Eriochrome Black
Hydroxynapthol Blue
Solochrome Black
is a compound capable of forming a Complexation reaction a t a favorable pH condition
Masking Agent
