Argentometric Tittration PDF

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argentometry and its types...

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12/15/2019

ARGENTOMETRIC TITRATIONS NAME FAIZA FAYYAZ ROLL NO 15 SESSION 2017-21 PRESENTED TO DR. RABIA REHMAN BUTT

1

ARGENTOMETRIC TITTRATION “Volumetric analysis in which a solution of silver nitrate AgNO3 is titrated against a halide or thiocyanate,resulting in the precipitation of silver halide or silver thiocyanate.” Ag+ + Cl-

AgCl

Ag+ +CN-

AgCN

It is also termed as Precipitate Titration. A special type of titrimetric procedure involves the formation of precipitates during the course of titration. The titrant react with the analyte forming an insoluble material and the titration continues till the very last amount of analyte is consumed. The first drop of titrant in excess will react with an indicator resulting in a color change and announcing the termination of the titration.

Example : AgNO3+ NaCl

AgCl + NaNO3

So, it is termed as argentometry,precipitimetry or precipitate titration

Derivation of the term  

The term is derived from Latin word”argentum” which means silver. It is used for the halide ion estimation

Principle of Precipitation Titration The main principle of the precipitation titrations is that the quantity of the added precipitating reagent or precipitant is equivalent to the substance being precipitated. Precipitation depends on solubility product and ionic product Q of the salt. “If the ionic product of the salt is greater than that its solubility product value then the precipitation of the salt takes place otherwise not, this is called the principle of precipitation.”

Ionic product is defined as; The product of concentrations of ions presents in a solution at any fixed temperature is called ionic product of the salt • It is denoted by Q

Solubility product is defined as; “Solubility product the product of molar concentration of ions raised to the power equal to its stoichiometric coefficient presents in the ionic equation in saturated solution at a fixed tempreature is called solubility product.” • It is donated by Ksp.

2 Depending upon the values of ionic product, the solutions can be classified into three different categories as follows: i. ii. iii.

If Q=Ksp, the solution is just saturated and no precipitation takes place. If Q>Ksp ,the solution is supersaturated and precipitation takes place. If Q...