The number of moles in a material is calculated as the product of its concentration and volume.

The probe is washed between each experiment to prevent cross-contamination of the different substances while blotting helps to remove excess water off the probe after rinsing.

Washing and blotting the probes during titration can cause excess water to be introduced to the substances during the experiment which changes the concentration of protons in the solution affecting the pH.

It must be noted that some of the amino acids in the solution will be on the electrode. During the titration, washing and blotting will progressively diminish the amino acid content in the beaker, resulting in incorrect findings.

Aspartic acid will convert to its neutral form, aspartate, by deprotonation in an acidic medium with a pH range of 1.88 to 2.2 and this represents pKa1.

In a medium with a pH range of 3.65 to 4.1, aspartate will deprotonate, which means it will lose an H+ ion or proton from its second carboxyl group, and this indicates pKa2.

Aspartate will deprotonate once again and lose a proton of the amino group to generate NH2 in a highly basic solution with a pH range of 9.68 to 9.9, indicating pKa3.

C1V1 = C2V2.

pH = pKa + Log([Salt]/[Acid]).

Parallax error is an error caused by not reading the burette at eye level can lead to a parallax error where the incorrect volume can be read, in turn affecting the HCl concentration.

Uneven distribution can occur if the mixture is not well blended; this might result in erroneous pH measurements in different sections of the container, and hence wrong overall findings.

Ensure the pH probe is always in its solution or kept wet when not in use and stored in a KCl solution rather than distilled water.

Storing the probe in water can cause the ions in the electrode glass to diffuse and create an equilibrium with the storage solution which decreases the chances of the electrode producing an accurate pH reading.

The pH meter must be calibrated regularly using its calibration buffers to ensure that the results of the experiment will be accurate and any changes made to the meter before the experiment is rectified.

Ensure both caps on the pH probe are placed back after use as they prevent the probe form drying out and being damaged by external forces which can cause inaccurate readings in the pH meter.