"A. Standardization of the sodium hydroxide solutioni. The burette was rinsed with 5 mL of 0.1 M sodium hydroxide solution. The rinsed solutionwas discarded. ii. The rinsing was repeated for two more time. iii. The burette was filled with 0.1 M NaOH solution. The volume was adjusted to the zeromark. A piece of labeling tape was used to identify this as the NaOH or base burette. Thisburette and solution will be used for the entire experiment.iv. The drop counter was calibrated using the burette with the sodium hydroxide solution. v. The starting volume of the burette was noted.vi. The drop rate was adjusted to 1 to 2 drops per second. 10.0 mL of the sodium hydroxidesolution was allowed to drip into a waste beaker. vii. The exact volume of the NaOH solution used was determined.viii. 0.3 to 0.5 g of potassium acid phthalate was weighed out into a clean 250-mL beaker. ix. Approximately 50 mL of distilled water was added to it and gently swirled to dissolve thesolid. x. 2 drops of phenolphthalein indicator solution was added to the beaker.xi. The pH electrode was calibrated using approximately 25 mL of pH buffers of pH 4 andpH 7 in 50-mL or 100-mL beakers.xii. The buffer solutions were saved in case the electrode has to be calibrated again during thelab period.xiii. The potassium acid phthalate solution was titrated with 0.1 M NaOH. When the endpoint was reached, the indicator solution turned red. The titration was allowed to continue for10 seconds after a permanent red color was obtained. xiv. The volume of 0.1 M NaOH used was determined.xv. The 250-mL beaker was rinsed well with the distilled water.xv. The titration procedure above was repeated 2 more times with fresh samples of thesolution.xvi. The molarity of the NaOH solution was calculated for each of the three titrations and thereadings were noted for analysis.PART II: TITRATION OF POLYPROTIC ACIDSMATERIALS NEEDED:Sodium hydroxide, NaOH (previously prepared and standardized)Phosphoric acid, H3PO4, 0.1 MSoft drink such as Mountain Dew, Sprite containing citric acidPhenolphthalein solution (1% by mass in ethanol)10 mL graduated cylinder - 1100-mL beakers - 2Burettes, 25-mL or 50-Ml - 2small funnels to fit the burettes -2LabPro unit and computer with pH electrode Drop counter Magnetic stirrer with stir bar- 3This experiment will determine the amount of citric acid in a soft drink. Here ascorbic acid,vitamin C, will interfere with this titration. Except for any ascorbic acid added, the soft drinkmust be free of any significant amount of vitamin C. Carbon dioxide, in the form of HCO3 orH2CO3 will also interfere with this procedure. PROCEDURE:i. 10.0 mL of 0.10 M phosphoric acid was measured into a 100 mL beaker. 25 mL of distilledwater was added to the beaker.ii. The solution was titrated with the standardized NaOH. When the end point would bereached, the pH should remain somewhat constant (approximately pH 11).iii. This procedure was repeated a second time using a new sample of the phosphoric acid. Ifyour results agree with the first titration, a 3rd trial is not needed.iv. Approximately 50 mL of the soft drink was placed into a 250 mL flask. The flask wasshaken several times to release the carbon dioxide in the drink. The flask was then vented. v. The shaking and venting of the flask was further repeated several times to remove as muchof the carbon dioxide from the soft drink as possible.vi. 10.0 mL of the soft drink was Measured into a 100 mL beaker. 25 mL of distilled wasadded to it.vii. This procedure was repeated a second time using a new sample of the soft drink. Therecordings were noted for the trials.Determining Phosphoric Acid content in soft drinks:Phosphoric acid is one of the weakest acids that is present in the carbonated beverages. It isthe most important component of all the cola soft drinks. Therefore, the concentration of thisacid is much higher than any other acids. Hence, with acid base titration its concentration canbe determined. A sample of soft drink is taken with sodium hydroxide solution. With thisconcentration of phosphoric acid, H3PO4 can be determined. From the first dissociation Hydrogen ions of phosphoric acid reacts with hydroxide ions fromthe NaOH in a one-to-one ratio in the overall reaction: H3PO4(aq) + OH– (aq) ?? ? H2O(l) + H2PO4– (aq). "