Report 3 - Practice Titration Potassium Hydrogen...

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Practice Titration, Potassium Hydrogen Phthalate (KHP) CHM3120C-903 Vincent Gallo U61917512 Shane Spiers February 14 th 2016
I. Introduction When determining the concentration of a solution in a standardization reaction, a titration technique is commonly used. In an acid-base titration, such as in this experiment, a known mass of the primary standard (the acid) is placed in an Erlenmeyer flask and dissolved in deionized water. In this case, potassium hydrogen phthalate C 8 H 5 KO 4 serves as the primary standard because it is an organic solid at standard conditions and its weight can be accurately determined. A solution of sodium hydroxide NaOH is then placed in a buret, making this solution the titrant. The buret allows for the slow and accurate addition of the NaOH solution to the KHP solution. A suitable indicator is chosen so that the analyst can see when all of the solution in the flask has reacted with the solution being dripped into it, this point is known as the equivalence point. Similarly to the equivalence point, the end point of a titration is the point at which a sudden change in a physical property occurs, such as indicator color or pH. Phenolphthalein is a common indicator used in neutralization titrations. The solution is considered neutral when it holds a very faint pink color for half a minute or more. A local change in color, where the drip enters the flask, means that in that specific location, there is more base than acid, and that neutralization will occur after a relatively small amount of titrant is added thereafter. Titrations are often recorded on graphs called titration curves, with the volume of the titrant being the independent variable and the pH of the solution depicted as the dependent variable.

Unformatted text preview: Practice Titration, Potassium Hydrogen Phthalate (KHP) CHM3120C-903 Vincent Gallo U61917512 Shane Spiers February 14 th 2016 I. Introduction When determining the concentration of a solution in a standardization reaction, a titration technique is commonly used. In an acid-base titration, such as in this experiment, a known mass of the primary standard (the acid) is placed in an Erlenmeyer flask and dissolved in deionized water. In this case, potassium hydrogen phthalate C 8 H 5 KO 4 serves as the primary standard because it is an organic solid at standard conditions and its weight can be accurately determined. A solution of sodium hydroxide NaOH is then placed in a buret, making this solution the titrant. The buret allows for the slow and accurate addition of the NaOH solution to the KHP solution. A suitable indicator is chosen so that the analyst can see when all of the solution in the flask has reacted with the solution being dripped into it, this point is known as the equivalence point. Similarly to the equivalence point, the end point of a titration is the point at which a sudden change in a physical property occurs, such as indicator color or pH. Phenolphthalein is a common indicator used in neutralization titrations. The solution is considered neutral when it holds a very faint pink color for half a minute or more. A local change in color, where the drip enters the flask, means that in that specific location, there is more base than acid, and that neutralization will occur after a relatively small amount of titrant is added thereafter. Titrations are often recorded on graphs called titration curves, with the volume of the titrant being the independent variable and the pH of the solution depicted as the dependent variable....
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