Complex Formation Titration Flashcards
These are formed when metal ions react with a ligand.
complexes or coordination compounds
These are ions or molecules that have a pair of unshared electrons capable of satisfying the coordination number of the cation
ligands
The amount of covalent bonds a cation form is dictated by the?
coordination number
Ligands are ions or molecules that have a pair of unshared electrons capable of satisfying the ________________________ of the cation.
coordination number
typical value of coordination number?
two, four, six
types of ligand
- monodentate
- bidentate
- polydentate
Titrations based on complex formation, sometimes called?
complexometric titrations
examples of monodentate ligand
- water
- ammonia
- fluoride ion
- chloride ion
- cyanide ion
- thiocyanate ion
- hydroiodide ion
- nitrite ion
examples of polydentate ligand
- diethylenetriamine
- triphosphate ion
- ethylenediaminetetraacetate ion
examples of bidentate ligand
- ethylenediamine (en)
- bipyridine
- ortho-phenanthroline
- oxalate ion
- carbonate ion
Formation of [Cu(NH3)4]2+ complex occur in a?
stepwise function
For any equilibrium, the larger the value of the _______________________, the more stable the product.
equilibrium constant
Equilibrium constant for complex formation is called?
formation constant (Kf)
Most ____________________ do not have an easily identifiable end point
unidentate ligands
_________________ ligands provide sharper end point.
polydentate
Contain two or more atoms that can simultaneously coordinate to a central metal ion, occupying two or more coordination spheres.
polydentate ligands
Chelating agents
polydentate ligands
Because of the multiple bonding site, these ligands react strongly with cations, thus providing sharper end points.
polydentate ligands
This is a hexadentate ligand with six binding sites, four negatively charged oxygen atoms in the carboxylate groups and two nitrogen atoms in the tertiary amino groups
Ethylenediaminetetraacetic acid (EDTA)
1st and 2nd dissociation
carboxylic group
3rd and 4th dissociation
removal of hydrogen from the amine group.
All metal–EDTA complexes have a _________ stoichiometry
1:1
name of the product of two constants
conditional formation constant
The conditional formation constant is dependent on the ______________.
pH of solution
it is dependent on the pH of solution
conditional formation constant
classification of EDTA titration techniques
- direct titration
- back titration
- displacement titration
- indirect titration
In __________________ you simply add an indicator to a buffered solution of the metal ion and titrate with standard EDTA.
direct titrations
In a ________________, an excess of EDTA is added to the sample solution containing an analyte metal ion.
back titration
This is useful when the analyte metal ion binds the indicator permanently, when the metal-EDTA complex is unstable, or when the metal ions form precipitates in the without EDTA.
back titration
It can be used if the analyte metal ions do not have a good indicator. In this case, a metal ion-EDTA complex is added.
Displacement titration
It is useful for anions which for insoluble precipitates like sulfate. Sulfate can be reacted with known amounts of Barium chloride.
Indirect Titration
The precipitate BaSO4 is ________________, and the remaining solution is ______________ with standard EDTA solution.
filtered, titrated
This is the most common type of EDTA titration
direct titration
