Discuss And Understanding Buffer Solutions

In this lab, the purpose was to determine the stability of a substance after adding an acid or a base. The results claim that liver and buffer are the most resistance to change in pH. Looking at figure 3, buffer and liver both maintain a stable pH even with the addition of an acid or base. However, potato and water have less buffer in them since their pHs did change. In figure 3, the potato acid’s pH level decreased by two, and the potato base’s pH level increased by two. The level of pH of a water acid decreased by 4, while the water base’s pH increased by 5. These results all tie to the fact that buffer is a substance that maintains a stable pH; the presence of buffer in organisms help maintain homeostasis by binding or releasing hydrogen

Buffers can be used to resist change in pH in an acid or base solution. The purpose of the lab is to understand the properties of buffers in relative concentrations, in the presence of a strong acid/base and dilution of buffer components the ammonia/ammonium buffer system. In this case, these laboratory techniques associated with buffers are performed to determine the pH values in diluted solutions. This is done by observing the Henderson-Hasselbalch equation. This represents the pH value by comparing the p value and the concentrations of a weak acid and conjugate base of a buffer solution, as long as assumptions are valid. From there, a pH vs log can be used from the values obtained. Then, the theoretical pH of solutions can be determined with the addition of a strong acid (HCl) and base (NaOH). From this, the effect of dilution can be viewed when plotting the calculated pH values vs dilution on the same graph.

For part B, 50 mL of an assigned 50 mL pH solution of either 1 M HCl, 1 M NaOH, lemon juice, and 50 mL of household bleach all in separate 250 mL beakers are to be used. For part C, a hot plate or ice are to be used to make the 1.0 mL assigned temperature specific water. This experiment will also use the 1.0 mL of 0.1 Phosphate buffer.

The procedure of this lab is to determine if liver and potato cells contain natural buffers that resist large change in pH as 1. NaCl or 1. NaOH are added to the solution.

A buffer is a solution that resists changes in pH when H+, OH-, or H20 is added. By using standard lab equipment, a lab pro diagnostic tool, and acidic and basic solutions, the pH can be found. By recording the pH while adding a base or an acid gradually to a buffer solution you can find the capacity of each buffer to resist drastic changes in pH. The best buffers will keep a solution from becoming either too acidic or basic with the addition of a strong base or acid.

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 problem that needed to be solved for this experiment was, “How are organisms able to survive and function with proficiency despite metabolic activities that have the disastrous ability to alter pH from a neutral to an acidic or basic environment?” This question needed to be answered by testing different biological materials, as well as tap water, in order to find out what allows modern day organisms to survive such hazardous conditions. A hypothesis that was formulated before experimenting was, “If type of substance is Tap Water, then the changes in pH will be more drastic because water, considered neutral on the pH scale, doesn’t contain a component that will prevent such a change, unlike the content of a buffer solution.” The independent variable for this experiment was type of substance, evidently because this was the part of the experiment that was constantly being changed from trial to trial. The dependent variable for this experiment was pH of the substance because the pH constantly changed depending on the type of substance was being experimented with. The control of this experiment was the tap water and buffer solutions, as the results of the data from the biological materials were constantly compared to the data from both of these solutions.

To make the buffer solution you need 0.2 mol dm-3 of Na2HPO4 and 0.1mol dm-3 of citric acid this will give 100cm3 of buffer. Here is how to get the different pH in the buffer solutions:

The buffer is a solution that minimises the changes in pH when small amounts of acid or base is added.There are two types of buffer solutions.They can either be acidic or alkaline.An acidic buffer is made by mixing equal amounts of a weak acid and its conjugate base.Similarly, an alkaline buffer has equal amounts of weak base and its conjugate

The appropriate pH range for a buffer solution is where the conjugate base to acid ratio is close to one.

The pH of a solution is the measure of the concentration of charged Hydrogen ions in that given solution. A solution with a pH lower than seven is considered to be acidic. A solution with a higher pH is a base. It is very important for organisms to maintain a stable pH. Biological molecules such as proteins function only at a certain pH level and any changes in pH can result in them not functioning properly. To maintain these constant pH levels, buffer solutions are used. A buffer solution can resist change to small additions of acids or base’s. A good buffer will have components that act like a base, and components that act like an acid.

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.

If an acid-base disturbance shifts the pH outside of the physiologic range, various control measures are activated to resist the change in pH. Compensatory mechanisms try to preserve the normal 20:1 ratio of bicarbonate to carbonic acid to keep the pH at normal range. The body works to maintain normal ratios through a compensation mechanism using renal and respiratory methods (Crowley, 2010).

Titration was used to determine the buffering capacity of 0.02 M monobasic potassium phosphate, 0.02 M dibasic potassium phosphate, a solution of equal mixture of the two, and water. Due to the mathematical relationship of pH to the concentration of hydronium ions we can interpret the results of this experiment to support the claims that monobasic potassium phosphate acts as a better buffer for bases but not acids and that dibasic potassium phosphate acts as a better buffer for acids but not bases. Similarly, a combination of the two act as the ideal buffer for the addition of both acids and bases. A weak acid and it salt can act as either an acid or a base as needed to neutralize the pH and keep it within a certain range.

1. The differences in pH value increases along the actual pH value. This is because the phosphate buffer has high buffering range in the pH range between 6 .Therefore the phosphate buffer with pH 6 and 7 which is more closer to the pKa value (pH 7) had a lower change in pH compared to phosphate buffer at pH 8 which moves away from the pKa.