Quantitative Analysis of Soda Ash by Double Indicator Method

2732 Words Aug 7th, 2012 11 Pages
Quantitative Analysis of Soda Ash by Double-Indicator Method
Mark Steven R. Santiago and Kristiene B. Sadiwa Institute of Chemistry, University of the Philippines, Diliman, Quezon City 1101 Philippines Date/s Performed: July 13, 2012; Date Submitted: July 19, 2012 Results and Discussions A mixture of carbonate (CO32-), bicarbonate, (HCO32-) and hydroxide (OH-) ions can be analysed and determined by titration with strong standard acid solution. Volumetric titrimetry can be employed to compute percent compositions of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), and sodium hydroxide (NaOH) in a soda ash sample through the application of neutralization concepts and titrimetric analyses. Volumetric titrimetry has been utilized in
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Moreover, NaOH cannot replace Na2CO3 for it generally do not satisfy above requirements and very hygroscopic in nature. On the other hand, 0.05 M HCl is called the standard solution. An ideal standard solution[3] is (1) sufficiently stable to determine concentration, (2) reactive with the analyte so that the time required between additions of titrant is minimized, (3) completely reactive with the analyte so that satisfactorily end points are realized, and (4) selectively reactive with the analyte that can be described by a simple balanced equation. The standardization of the titrant aims to know the exact concentration of the titrant (its deviation from the measurement done). Two basic methods are used to establish the concentration of standard solutions: (1) direct method, in which a carefully weighed quantity of a primary standard is dissolved and diluted to an exactly known volume in a volumetric flask, and (2) standardization by titrating (a) weighed quantity of a primary standard, or (b) a measured volume of another standard solution. In the

experiment, the standard solution has been standardized using method 2b[3]. The standard solutions
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