Study Set Content:
- use of another standard solution
Secondary Standard
- use of a carefully weighed sample of a substance of known purity
Primary Standard
Four (4) Requirements must be met if the reaction to be used is titrimetric analysis:
a.reaction must proceed completion.
b.the reaction must proceed in a stoichiometric manner.
c.a suitable end-point detecting device must be used (indicators, electrodes….)
d.for direct titrimetric methods the reaction must be rapid so a sharp end point is discernible.
Reactions may be made to go in completion in several ways:
a.formation of a slightly dissociated substance as a reaction product.
b.removal of one or more products of reaction as precipitate.
c.removal of an ionic substance, such as complex ion.
d. by adding an excess of one reactant.
Chemical reactions used in titrimetry:
a. neutralization (acid-base) in aqueous and non aqueous solvents.
b. oxidation-reduction
c. precipitation
d. Complexation
- are chemical processes in which an acid (proton donor) reacts with a base (proton acceptor). The product is salt and water.
- These most commonly use a pH indicator, a pH meter to determine an end point.
Neutralization Reactions (acid-base reactions)
- are based in the formation of complex between the analyte and the titrant
- chelating agent EDTA
EDTA - edetic acid or etheylenediaminetetraacetic acid
Complexometric Titrations/Complexation
based on the oxidation reduction reactions between the analyte and the titrant
Redox titrations
- Formation of insoluble substances to be used for assay.
- Fajan
- Mohr
- Volhard
- Liebig
- Gay-Lussac
Precipitimetric Method
- Formation of insoluble substances to be used for assay.
- Fajan
- Mohr
- Volhard
- Liebig
- Gay-Lussac
- general formula use for percentage purity of a sample determined by direct titration
Calculations in Volumetric Analysis:
Standardization of IN HCL
PRIMARY STANDARD
sodium carbonate
Standardization of IN HCL
Titrant
Hydrochlovin Acid
Standardization of IN HCL
INDICATOR
methylved
Standardization of IN HCL
TYPE OF ASSAY
Standardization
Standardization of IN HCL
Faintly Pink
SODIUM CARBONATE
Na2CO3
HYDROCHLORIC ACID
HCl
SODIUM CARBONATE MW
106
Standardization of IN HCL Chemical Formula
NaHCO3 → Na2CO3 + H2O + CO
