Lab Report Standardizing a Sodium Hydroxide Solution Kathryn Charuk CHEM 1411 T 1:00, Mr. Pritchard
Lab Report for Determining the Molar Concentration of a Sodium Hydroxide Solution Abstract: The purpose of this experiment was to homogenize a sodium hydroxide solution by using the solution to titrate a solution of potassium hydrogen phthalate. KHP (potassium hydrogen phthalate) is able be titrated to standardize a NaOH solution. The reaction of the solution is KHP (aq) + NaOH (aq) NaKP (aq) + H 2 O (l); Thus creating the titrated solution. This is considered an acid, base solution experiment. Mixing an acid and a base yields the products of water and salt. The solution should turn a consistent light pink tinge. The color is discovered through the use of the acid base indicator Phenolphthalein. The concentrations are expressed through molarity. The average molarity of the solution was .385 moles. Background : A solution is characterized by a homogeneous mixture. A homogeneous mixture is a compound of more than one element that appears to be uniform. The exact concentration of the solution can determine how much of the solute is present in a specific volume of a solution. In order to standardize a solution the concentration has to be determined. A standard solution has a known concentration. The concentration of a solution can be expressed as the number of moles of solute present in one liter of solution, which is Known as molarity (M). Titration is a measured amount of a solution of unknown concentration that is added to a known volume of a second solution until the reaction between the two is complete. NaOH solutions need to be standardized because of the possibility of reacting with the oxygen in the air. KHP is able to be titrated to standardize a NaOH solution. Phenolphthalein is an acid-base indicator that is colorless in acidic solutions and pink in basic solutions, especially those that have an excess of base. The acid base indicator is a compound whose color depends on the acidity of a solution. This process used to determine if and when the neutralization reaction is complete. To determine titration a burette is used. A burette is a piece of glassware used to accurately deliver varying KHP (aq) + NaOH (aq) NaKP (aq) + H 2 O (l); Molarity = moles of solute Liter of solution
volumes of a liquid or solution. The solution in the burette is called the titrant. When a drop of titrant causes the indicator to change color the titration has ended.
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