PRACTICAL- I
VOLUMETRIC ANALYSIS
The method to determine the exact amount of the substance in a given sample is termed as quantitative analysis volumetric analysis is a branch of quantitative analysis involving accurate measurement of volumes of reacting solutions. The volumetric analysis is very much in use due to simplicity rapidity accuracy and wide applicability. The reacting substances are taken in the form of solutions and made to react. The concentration of one solution is determined using another suitable solution whose concentration is accurately known. A known volume of one solution is measured with a pipette and taken in a conical flask. The other solution is taken in a burette and run into the first solution till the chemical reaction is just complete. The volume of the second solution is read from the burette and the two volumes are compared. Various terms used in volumetric analysis are given below: Titration The process of adding one solution from the burette to another in the conical flask in order to complete the chemical reaction is termed titration. Endpoint It is the exact stage at which chemical reaction involved in the titration is just complete Indicator It is a substance which will show the end point of the reaction by change of colour. For example phenolphthalein and methyl orange are indicators used in acid alkali titrations. Potassium permanganate itself acts as an indicator in potassium permanganate titrations. Acidimetry and Alkalimetry Titration: Acidimentry refers to the titration of alkali with a standard acid and alkalimetry refers to the titration of an acid with a standard alkali.
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Permanganimetry Titration: The titration involving KMnO4 is called permanganimetry titration. In presence of dilute H2SO4 KMnO4 oxidizes ferrous sulphate to ferric sulphate and oxidizes oxalic acid to CO2 and H2O. Normality: The strength of a solution is expressed in terms of normality. Normality is the number gram equivalent