Strong Acid Solution example essay topic

Introduction The two types of aqueous solutions in chemistry that are being experimented with are called acids and bases. A strong acid solution is one that consists of a solution that is less than seven ph factor. The basic solution is one that consists of greater than seven on the ph scale. In this experiment standardization of a chemical reaction is used to determine the concentration of the acid and the base solution. Potassium Hydrogen Phthalate (KHP) mixed with Sodium Hydroxide (NaOH) is a good source of standardization. In the solution of KHP and water add the Sodium Hydroxide by titrating using a buret.

This can give you the point where the acid has been neutralized. The point of neutralization is referred to as the ending point The chemical equation used to indication this point is shown in reaction 1. HIn +H 20 H 30 +In- (1) An indicator used for this experiment was phenolphthalein which has a transition range of 8.3 to 10.0 and its color change is from colorless to pink. At the start of the titration, the analyte solution pH is that of a strong acid. PH = -log [H 3 O+] = -log [. 1 M] = 1 The equivalence point of the titration when there are equal amounts of strong acid and strong base, therefore making the pH of 7.00 that is equal to water.

Since the transition range indicator is above 7.00 we can say for certain that the end point occurs soon after. So standardization of the NaOH solution from titrating against a primary standard KHP will allow us to determine the concentration with accuracy. Experiment In the beginning of this lab we had some preliminary items to do before we could perform the experiment. We prepared a stock solution of Sodium Hydroxide by adding 75 mLv and diluted with 750 mL of DI water in a Nal gone bottle. The preparation of the three solutions of KHP were done by weighing three samples of ~0.5 g KHP in a 250 mL Erlenmeyer flask.

By adding 100 mL of DI water to each of the three flasks formed the acidic solution. The indicator which is phenolphthalein, 2 drops added to each of the three flasks. We began to tritated the NaOH into the flask noting that a pink color would appear, but when we swirled the flask it became colorless. We used a white background to observe the color change easier. We tritated 22 mL of solution fairly quickly while constantly swirling the solution. When 25 mL of solution had be tritated we started noticing the pink color in the solution wasn't disappearing like it was earlier.

By reading the buret volume to two decimal places we arrived at the end point. The average for the three trials is 27.03 mL. In part two we accurately weighed ~0.7 g of an unknown and placed it into three 250 mL Erlenmeyer flasks. To each Erlenmeyer flask we added 100 mL of DI water and dissolved. In order to get the entire unknown to dissolve we used stirring rods to crush substances as well as still the solution.

Again adding two drops of phenolphthalein to each flask we began the experiment (titrating). We tritated to 14 mL fairly quickly because the color change in the flask was not lasting but a brief second. We then proceeded to a drop wise method and the average of these were 16.93. The first three titrations were carried out with phenolphalein.

This means that KHP is a weak acid and, titrating it with the strong base NaOH, the equivalence point should be greater than 7. This proves to be true because the mean is 9.02. The amount of KHP weighed within the. 05 grams recommended by the experiment. The weight of the KHP and the unknown substance forms weak acid.

These two substances worked well with the strong base NaOH to standardize the reaction. The dissociation of an indicator is concurrent with a color change or some other physical change that informs us of the solutions approximate pH. A decreased amount of H 30+ makes it probable for the dissociation reaction of the indicator to occur since equilibrium must be obtained. The continued reproduction of a very faint pink color change is difficult to do. There will be some variation in the color due to human limitation of observing colors consistently even though we observed on a white background. The errors in recording measurement by using an analog device could be somewhat normal.

The error associated with things like the indicator and reading burettes cannot be eliminated. We can, however, minimize this error as much as possible thought using good techniques. Continuation of these experiments will increase our ability to read the burette accurately. In using an analytic balance the errors should be minimal as long as the balance was zeroed at the beginning of the experiment and the weights were in the acceptable range of 0.5 grams.

Conclusion Standardization is a process used to establish accurate concentrations of solutions. Using KHP as a primary standard, a solution of NaOH has been standardized. My standard deviation was +/-. 405.

My mean was. 902. My results showed that KHP is a weak acid. Reference An lier, Keith; Breen, Nancy; Nguyen, Marie Experimental Chemistry II C 126 Third Edition Re "chemically equivalent" reactants represents the point at.