Fajan's method of titration uses the reaction that occurs between the precipitate and the indicator during titration. The surface of colloidal AgCl absorbs fluorescein and its derivatives. The first drop of Ag+, following the use of all of the chloride, reacts with fluorescein resulting in a reddish color.Continue Reading
Scientists use a dye for an indicator, such as dichlorofluorescein, and it is an anion in solution. Anions are groups of atoms or single atoms with gained electrons. Chloride ions are excessive in a chloride solution, so they are responsible for the formation of the primary layer on the precipitate someone uses, with the second layer being the cations of sodium. Cations are a group of ions or individual ions that have a positive charge. During electrolysis, they always tend to move toward the negative electrode.
At the end point, or the completion of the reaction, the silver ion is excessive. This results in the primary layer now being silver ion. It attracts the indicator's ions because it now has a positive charge and forms the secondary layer. When comparing the absorbed indicator and the free indicator, the color is different. This gives scientists a visible end point so that they know when the reaction is complete.Learn more about Chemistry
Titration is a method of chemical analysis. It's used to determine the exact amount of a reactant in a flask by determining the exact endpoint of a reaction.Full Answer >
A solid precipitate can be produced from the combination of two aqueous, ionic solutions. Whether or not the two solutions form a precipitate for certain can be predicted using a series of rules for the solubility of inorganic compounds. The ions in the two compounds interact with each other, but they must produce a compound that is solid and insoluble for it to be considered a precipitate.Full Answer >
A supernatant liquid occurs in the chemical process of precipitation, and it is typically a clear liquid free of precipitate located above the solid during settling. A supernatant is considered a deposit, and the term itself is from the Latin word "supernatant," meaning to float from.Full Answer >
Harper College explains that forming a precipitate, color changes, gas formation and temperature change are signs of a chemical change. The University of California, Davis adds that the presence of odor also indicates a chemical change. There are only five indicators of a chemical change.Full Answer >