Solution Of A Weak Acid And Sodium Hydroxide Solution

1. To titrate a hydrochloric acid solution of “unknown” concentration with standardized 0.5M sodium hydroxide.

The purpose of this semester long experiment was to determine an unknown organic acid. An organic acid is an organic compound with acidic properties. A base reacts with acids to form salts. Titrations are used to determine the concentration of unknown substances. The purpose of the KHP experiment was to determine the molarity of NaOH. HCl titrations are mainly to check technique and used to verify the molarity of NaOH solution. The hypothesis is that this acid is C4H3OCOOH.

weak bases). After ranking the pH of these solutions, you will then test your predictions in the laboratory.

To start out this study the difference between acids and bases has to be identified. Acids have very low pHs and have a high concentration of hydronium ions, while bases have a high pH and have a high concentration of hydroxide ions. The difference between strong bases and acids, and weak bases and acids is the amount of dissociation. Strong bases and acids dissociate a large amount and let go of their ions in solution, while weak bases and acids may only let go of some of their ions. This is important because if the unknown solutions aren’t strong acids or bases then using their ions to calculate the pH of the solutions will give false results (Diffen 2012).

The purpose of this experiment was to determine the pKa, Ka, and molar mass of an unknown acid (#14). The pKa was found to be 3.88, the Ka was found to be 1.318 x 10 -4, and the molar mass was found to be 171.9 g/mol.

By first measuring the pH levels of solution A through E with a pH meter, it gives a numeric reading to ph balance to a solution. Next, add in a natural indicator called anthocyanin made from the pigment from a red cabbage into each solution and mixed it until there is a distinct color and recorded on the chart. Finally, by looking at the result of the pH reading level that

Only 20 mL of amino acid was used for both titrations. Around 5mL of HCl was used in the acid titration of the unknown but only 1.55 mL of base was used for the Basic titration. The table of acidic and basic titrations is attached where it shows that the amino acid therefore was acidic since it took a lot more acid than the base for titration. Molar equivalence was calculated using the concentration and volumes of amino acid and titrants. A graph was plotted which showed two pH value, one at -1.5 and the other at 0.5. The pH at -1.5 was 2.53 and at 0.5 was 10.15. The pI was then calculated to be 6.34. The unknown amino acid, AA-01-04, was concluded to be Aspartate or Aspartic acid by examining the titration curve and pH’s at the Molar equivalence.

To begin, three sets ofabout 0.3000g of KHP are weighed out on an analytical balance. Put the three sets of KHP into three separate, labeled flasks. All three sets of the KHP is then dissolved with approximately 50mL of deionized water. Next, a buret is used to start the actual titration. Buret is initially filled to 0.00mL mark with the NaOH solution, this is recorded as initial volume. Next, add 2-3 drops of phenolphthalein indicator into each of the three flasks containing KHP. A magnetic stir bar is then added to the first flask, and placed above a stir plate. Everything is positioned under the buret. Stirrer is put on medium speed and the titration can start. Slowly release the NaOH into the KHP flask. As the end point is reached, a pink color will be seen in the flask. When the lightest pink possible remains in the solution for more than 30 seconds titration is complete. The final volume is recorded, and the same steps are taken for the other two sets of KHP solution. Finally, blank titration is completed to determine deviation.

Caution – Hydrochloric acid is corrosive to eyes, skin and clothes. Wearing a lab apron, rubber gloves, goggles, and a face shield is essential. Rinse any spills on skin or clothing with plenty of cold water. Clean up spills immediately – ask your instructor for help.

During a titration the pH of the solution will be monitored using a pH meter from that we get a titration curve. The titration curve is then used to determine the equivalent molecular weight and Ka value of the unknown weak acid, from that we are

Using Graph 1: The Volume of Titrant Added in order to reach the Endpoint and the Corresponding pH Values, observe the vertical line of each titration and see the points in which the horizontal lines intersect it. These points give the

50 mL of an unknown amino acid was given and its initial pH was measured. Next, the amino acid was titrated with .1 N NaOH in increments of .5 mL. With every .5 mL of NaOH added to the amino acid solution pH of the mixture was taken and a titration curve was created. Henderson-Hasselbalch equation was used to determine the pKa’s of the unknown amino acids. pKa1 was determined to be 2.39. Equivalence also known as the pI point occured at a pI of 7.94.

First, three titration curves and three second derivative curves were created to determine the average pH at the half-equivalence point from the acetic acid titrations. Titration curves were used as visuals to portray buffer capacity. The graphs and a table, Table 1, that showcased the values collected were created and included below. The flat region, the middle part, of Figures 1, 2 and 3, showed the zone at which the addition of a base or acid did not cause changes in pH. Once surpassed, the pH increased rapidly when a small amount of base, NaOH, was added to the buffer solution. Using the figures below and

Here are some of the things that I learned in lessons 07.03 (pH), and 07.04 (Equilibrium). The formula to calculate the pH of a solution is pH = - log [H3O+]. A titration is a laboratory technique used to calculate the concentration of a chemical. You are performing an acid-base neutralization reaction. For example, let’s say we have some HCl that we do not know the concentration. We can react it with a base, such as NaOH. You start by placing the substance of a known concentration in a buret, such as a 0.25 M NaOH solution. Then, place the chemical that you do not know the concentration of in a flask under the buret, such as HCl. We need to add an indicator to the flask since most reactions are colorless. You will ‘titrate’ the NaOH until you reach the endpoint, which means that you will allow the chemical in the buret, called the titrant, to flow into the flask. At the end point, the solution will have a light pink color. Once you determine how much of the titrant, NaOH you used, you can use stoichiometry to calculate the concentration of the unknown, HCl.Chemical equilibrium is when the forward and the reverse reactions are occurring at the same rate. If K is greater than 1, that means there are products than reactants are equilibrium. If K is less than 1, there are more reactants than products at equilibrium.As more products are made, the rate of the forward reaction will decrease.The rate of the

The styrofoam cups were used to store the acid (cup was labeled A) and base (cup was labeled B) prepare for them to be mixed. A lid was put on cup A and then the temperature probe was inserted to begin to measure the temperature