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When I am using back titration and direct titration as my two methods for determining the purity of aspirin tablets. doesn't the direct titration not take into consideration of the excess sodium hydroxide added to the aspirin?
In both these titrations when I reach the end-point it turns pink but I kept these solution the next day and they turned back to colourless. Is this meant to happen and what chemical reaction has happened here?
I titrated this again with more sodium hydroxide till the end-point then added this to the overall amount of NaOH i added in the flask.
Is the only difference between back titration and direct titration not addding the HCl at the end to determine the excess amount of NaOH?
Are there any methods for direct titration.
Would really appreciate any help.
The best you can obtain is an end point lasting 20-30 seconds. Any excess base will slowly hydrolyze the ester and liberate acetate ion from the act's because aspirin is such a weak acid that it reacts slowly with the NaOH, making it difficult to accurately get a good endpoint in a reasonable time.
With back titration, you react with an excess of NaOH (known amount), heat it to make the reaction go to completion quickly, then use HCl to determine the amount of NaOH that is remaining. This reaction will go quickly, and is much easier to measure.elylsalicylic acid,aspirin.
What else can I help you with?
What do you use a burette for?
The pricipal use is in the volumetric titration - a method of quantitative chemical analysis.
What are complexometric titration method?
Complexometric titration is a type of volumetric analysis used to determine the concentration of metal ions in a solution by forming complexes with a specific reagent. In this method, a chelating agent is typically used to form a stable complex with the metal ion, and the endpoint of the titration is usually determined using a colorimetric indicator or a pH meter. This technique is commonly employed in the analysis of a variety of metal ions in solution.
Which type of the analysis the titration is?
Titration is a method of chemical analysis; for example: - volumetry - potentiometric titration - amperometric titration - radiometric titration - Karl Fisher titration - spectrophotometric titaration - viscosimetric titration and other methods
Difference between iodometry and iodimetry?
When an analyte that is a reducing agent is titrated directly with a standard iodine solution, the method is called "iodimetry". When an analyte that is an oxidizing agent is added to excess iodide to produce iodine, and the iodine produced is determined by titration with sodium thiosulfate, the method is called "iodometry".
How does ultrasonic titration work in drug screeningblood analysis?
Ultrasonic titration is not commonly used in drug screening or blood analysis. Titration is a method used to determine the concentration of a substance in a solution by adding a reagent of known concentration until a reaction is complete. In drug screening and blood analysis, other techniques such as chromatography, immunoassays, and spectrophotometry are typically used due to their sensitivity and specificity.
Easy Analytical techniques zinc sulphate Ferrous sulphate Copper sulphate through titration method?
For analysis through titration method: Zinc sulfate can be titrated using EDTA as the titrant. Ferrous sulfate can be titrated using potassium permanganate as the titrant. Copper sulfate can be titrated using sodium thiosulfate as the titrant.
What can affect purity of aspirin?
Firstly place 100 to 150 mg of aspirin into a 125 ml conical flask. Next proceed to mix in 15 ml of 95% ethanol solution and add 2 drops of phenolphthalein indicator. Then use the titration method to mix this solution against a standard solution of sodium hydroxide from a burette. Using the value obtained from the titration calculate the molarity of the aspirin. Then calculate the ratio of the observed molarity of aspirin with its theoretical molarity and finally multiply this ratio with 100 to obtain the percentage purity of the aspirin sample.
Need of blank titration?
Blank titration is typically used in analytical chemistry to account for any impurities or chemical interference in the titration process. It involves running the titration without the sample to measure any background signal or end point shift caused by impurities, which is then subtracted from the titration with the sample to obtain accurate results. This method helps in ensuring the precision and accuracy of the titration analysis.
What is visual titration?
Visual titration is a method of determining the concentration of a substance in a solution based on a change in its color or appearance. It involves adding a titrant incrementally until a color change occurs, indicating the endpoint of the reaction. Visual titration is commonly used in qualitative and quantitative chemical analysis.
What is substitution titration?
Substitution titration is a chemical analysis technique where a titrant is added to a solution containing an analyte to replace one ligand or ion with another. The endpoint of the titration is reached when the substitution reaction is complete. This method is commonly used in complexometric titrations to determine the concentration of metal ions.
What is mean by complexomatic titration?
Complexometric titration is a type of volumetric analysis in which the formation of a complex between the analyte and a titrant is used to determine the concentration of the analyte. This method is often used to determine the concentration of metal ions in a sample solution.
What is the principle of precipitation titration?
Precipitation titration is a method of volumetric analysis that involves the formation of an insoluble precipitate as the endpoint of the titration. The principle is based on the reaction between the analyte and titrant to form a sparingly soluble salt, which is visible as a precipitate. The endpoint is reached when the precipitation is complete, indicating that the reaction has finished.
