Complexometry Flashcards
The process based on the formation of a complex substance in the course of analysis.
Complexometry (complex-formation method)
Complexation Method uses:
Calcium (Ca)
Copper (Cu)
Mercury (Hg)
Magnesium (Mg)
Zinc (Zn)
Aluminum (Al)
Bismuth (Bi)
EDTA will react with metal ions to form a water-soluble stable complex or a ?
chelate compound
When a metal ion combines with a molecule which donate electrons, the resulting compound is termed a ?
complex
The complex is called a chelate if?
If the combining molecule contains two or more groups that donate electrons.
The groups bound to the central ion are called ?
Ligands
Types of Ligands
1,4,7-triazaheptane
Ethane-1,2-diamine
Measure of the strength of the interaction between the reagents that come together to form the complex.
Stability Constant
Stability constants should be greater than ?
greater than 8
These elements forms very weak complex.
Li, Na
Ks is below 8
Ag and Ba
Colored metals
Fe and Cu
Organic compounds which form colored complex ions with metal ion in high dilutions.
Indicators
Qualities of a good indicator are:
- sharpness of color change at the endpoint
- specificity of the indicator for the metal ion under the conditions of the analysis
- stability constant smaller than that of the metal-EDTA complex-i.e. the indicator must give up the metal ion to the titrant EDTA for complexing and not compete with it
Qualities of a good indicator are:
_________ of color change at the endpoint
sharpness
