The reaction between acid and base frequently yields the merchandises of salt and H2O.
Matter and Motion - Winter Chemistry Laboratory 4: The objective of this lab is to standardize a 0. In this experiment you will determine the weight percent of potassium hydrogen phthalate abbreviated as KHP, which does NOT mean potassium hydrogen phosphide!
To do this, you will titrate a known mass of the material with sodium hydroxide solution, which you will prepare and standardize see below.
The analysis will be performed two ways: You will then compare the results to confirm the reproducibility of the result. The concentration of the sodium hydroxide will be determined in other words, the solution will be standardized by titration of pure KHP, a weak acid.
The pure KHP is a good example of a primary standard because it is relatively cheap and non-toxic, very pure, and stable. These properties make it ideal for standardizing base solutions. You will titrate the KHP with your prepared NaOH solution in sets of three samples until the relative standard deviation standard deviation divided by the mean is 0.
At that point, you can then analyze your unknown sample. Store in a plastic bottle with a screw-top cap to minimize exposure to air. Dissolve each in about 25 mL of deionized water. Add three drops of phenolphthalein indicator to each.
Titrate one sample crudely to find the approximate endpoint. Then, based on your result, titrate the other three more carefully, being particularly careful not to titrate past the endpoint. At the endpoint, the solution should have a faint pink hue which should fade after 15 - 30 seconds.
The relative standard deviation should be less than 0. If it is not, repeat the standardization with three new samples of pure KHP. Measure four samples, each about 0. Transfer to Erlenmeyer flasks and dissolve in deionized water as was done with the pure KHP samples.
Titrate with the standardized NaOH solution. As before, the first titration can be crude - this provides a rough estimate of the purity.
The final three titrations should be done more carefully. Calculate the mean percent of KHP in the unknown, the standard deviation and the relative standard deviation.
Dissolve the unknown in deionized water. Before adding any NaOH, measure the initial pH of the solution. Add NaOH titrant in approximately 0. Then add titrant in about 0.
Then add additional NaOH in about five 0. Determine the endpoint by finding the maximum point on the derivative plot. Calculate the weight percent of the KHP in the unknown using this value and compare to the result obtained using your indicator.Volume of NaOH used Part II.
Determination of the Molar Mass of an Acid Unknown # n- Run Number Mass of test tube + sample Mass of test tube - sample Mass of sample, NaOH buret NaOH buret L ss ML Initial reading timberdesignmag.com Volume of NaOH used.
Table 1 Standardization of NaOH using KHP Weight of Std KHP Mass of Pure KHP Corrected Volume of NaOH Molarity of NaOH g g mL mL Table 1 shows the calculated molarity of HCl and NaOH solutions from the standardization of NaOH using KHP.
Part 1: Standardization of NaOH. We will write a custom essay sample on Titration of Acids and Bases Essay specifically for you.
for only $ $/page. Order now. Search. Related Essays. Standardization of NaOH and determination of Molarity Essay Sample ; send me this sample. In the first standardization the molarity of a sodium hydroxide solution (NaOH) will be determined by titrating a sample of potassium acid phthalate (KHP; HKC 8 H 4 O 4) with the NaOH.
In the second procedure the standardized NaOH will be used to determine the molarity of a hydrochloric solution (HCl). concentration desired (usually within 10%), determination of the concentration by direct titration against a primary standard, and a test of the accuracy of your determined concentration by comparison with a known standard.
Standardization of NaOH and determination of Molarity Essay Sample.
Objectives. 1. Preparation and standardization of a M NaOH solution 2. To learn the technique of titration.