Titration Of A Strong Acid

By using the pH paper to measure the solutions A through E it would point out what substance is an acid and which one was basic. Also, by adding Bromothymol blue and Phenolphthalein afterwards to the solution it would indicate what color it would turn to when mixed into an acid and a base.

Chemistry 102 is the study of kinetics – equilibrium constant. When it comes to the study of acid-base, equilibrium constant plays an important role that tells how much of the H+ ion will be released into the solution. In this lab, the method of titrimetry was performed to determine the equivalent mass and dissociation constant of an unknown weak monoprotic acid. For a monoprotic acid, it is known that pH = pKa + log (Base/Acid). When a solution has the same amount of conjugate base and bronsted lowry acid, log (Base/Acid) = 0 and pH = pKa. By recording the pH value throughout the titration process and determining the pH at half- equivalence point, the value of Ka can be easily calculated. In this experiment, the standardized NaOH solution has a concentration of 0.09834 M. The satisfactory sample size of known B was 0.2117 g. The average equivalent mass of the unknown sample was found to be 85.01 g, pKa was found to be 4.69, which was also its pH at half-equivalence point and Ka was found to be 2.0439×〖10〗^(-5). The error was 1.255% for equivalent mass and 0.11% for Ka. In other word, the experiment was very precise and accurate; the identity of the unknown sample was determined to be trans-crotonic by the method of titrimetry.

When compared to distilled water (Figure 2), the pH of the buffer solution showed a stable pH, showing only a .2 fluctuation between the solution with the strong acid (HCl) and the solution with the strong base (NaOH). Distilled water, on the other hand, showed a 10.55 fluctuation of pH from the same amounts of the same solutions added, supporting the fact that buffer solutions are able to resist pH changes. Distilled water is made of H2O ions so it isn’t able to neutralize H+ and OH- ions, it has to have another solution added to do so. The same go for other species that are simply one element or compound, they also tend to change pH more readily than buffers. Buffers have acidic compounds that are able to neutralize those ions, however they will change pH as readily as other solutions if enough of HA isn’t present.

The antacid each group added to their HCl solutions all increased the pH of the HCl to a certain degree. In order to determine the best antacid, the trial/antacid where the least amount of NaOH was added in order to turn the HCl solution pink needs to be identified. This tells which solution was the most basic before the addition of NaOH, and consequently tells which antacid increased the pH the most, making it the

The purpose of the experiment was to determine how a buffer works and how to use an acid-base indicator. The way a buffer works was determined by observing the changes in pH of solutions of different concentrations weak acids and their conjugate bases to determine how a buffer affects the pH change. The solution of 10 mL of 0.20 M CH3COOH and 10 mL of 0.20 M CH3COONa had slighter changes in pH than the solution of 10 mL of 0.0020 M CH3COOH and 10 mL of 0.0020 M CH3COONa. Both of these solutions were buffers, shown because they had slighter changes in pH than the solutions with only the weak acid or conjugate base and water. The determination of how buffers work was also tested with observing that the solution of NaC4H3O4 and Na2C4H2O4 had smaller

An acid produces H+ ions in an aqueous solution, while a base produces OH-. Neutralization is when a substance has equal amounts of H+ and OH- ions. The pH of a neutral substance is 7. An acid and a base are reactants in the reaction.

Within an acid-base titration the titration curve resembles the strengths of the corresponding acids and bases. A strong acid will correspond with a weak conjugate base, and a weak conjugate acid will correspond with a strong base. This is based on the Bronsted-Lowry model. The weak acid will donate protons to the hydroxide ion. Weak acids will have a low Ka value, the Ka value is the tendency of the acid to dissociate:

Water was added until the mark is reached. For bottle samples NO. 2 and 3 (both will be buffer solutions), the pH was adjusted into either two of the three different pH level groups, 6.5-6.7, 7.0-7.2, or 7.6-7.8. The electrode is placed in bottle NO. 2, while titration began. The solution is mixed with a stirring rod, not the electrode. Titrate until the pH reading is between one of the three pH ranges listed above.

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

means the solution is neutral, 9 - 11 for a weak base, and 12 - 14 for a strong base. There are three theories that are used to define a base and an acid. The first theory is the " The Arrhenius Theory " this theory says an acid produces hydrogen ions, H+ in water solution and a base produces hydroxide ions, OH− in water solution. The second theory is " The Bronsted - Lowry Theory ". This

Acid-base reactions reach the equivalence point when an equal number of moles of acid react with the base. As soon as we see a change in color of the solution, the reaction is complete and the titration can be stopped. The change in color are due to the indicator.

For this experiment, titrations on a weak acid, acetic acid, and a buffer were performed. Acetic acid was titrated with NaOH in order to observe the half-equivalence point as well as the equivalence point. Then, the buffer and the buffered acetic acid solution prepared faced additional titration with NaOH and HCl to evaluate the differing buffering effects following the addition of a strong acid and strong base. Finally, the buffer’s buffering capacity was calculated. If the experiment were to be repeated, it would be interesting to observe the buffering effects following a titration between a weak base and a buffer instead with greater concentrations. The change in the concentration following the preparation of buffer with a weak base and its conjugate acid would pose for an interesting experiment to observe an increase in the buffering capacity.

Neutralization of an acid using a base Introduction: Last week I had a chicken cheese burrito and got a massive heart burn. My mom gave me some tums and the heartburn went away. This made me think about antacids and how much of the table is actually useful? The reaction of NaOH when titrating with KHP or an CaCO3 (Antacid) could be expressed with the equation (KHP) – NaOH(aq) + KHC8H4O4(aq)

“The pH of the solution formed from the reaction of a weak acid with a weak base depends on the relative strengths of the reactants. For example, if the acid HClO has a Ka of 3.4 x 10-8 and the base NH3 has a Kb = 1.6 x 10-5, then the aqueous solution of HClO and NH3will be basic because the Ka of HClO is less than the Ka of NH3.” (Helmenstine, 2004)

An acid-base titration is the determination of the concentration of an acid or base by exactly neutralizing the acid/base with an acid or base of known concentration. This allows for quantitative analysis of the concentration of an unknown acid