THE DETERMINATION OF GASTRIC ACIDITY BY THE GLASS ELECTRODE

A concentration cell is a type of a voltaic cell constructed by connecting two almost identical half-cells, both based on the same half-reaction and using the same electrode, differing only in the concentration of one redox species. A concentration cell's potential, therefore, is determined only by the concentration difference of the particular redox species.
Consider the following voltaic cell:

The human body carefully regulates the internal pH of different organs to maintain homeostasis. For example, while the blood plasma maintains a neutral pH of 7, the stomach lumen has an acidic pH of 1.5 - 3.5. The low pH of stomach lumen helps kill pathogens in the food and break down complex food molecules.
The acid-secreting gastric mucosal epithelial cells (parietal cells) lining the stomach lumen maintain the low pH in the lumen. Numerous ion transporters and channels on these parietal...

The titration of a polyprotic base such as sodium carbonate with a strong acid such as hydrochloric acid results in two equivalence points on the titration curve. At the first equivalence point, the carbonate ions in the base are completely converted to bicarbonate ions. The second equivalence point corresponds to the complete conversion of bicarbonate ions to carbonic acid, which dissociates into carbon dioxide and water. The region before the first equivalence point corresponds to the...

In acid-base titrations, conductance measurements are utilized to detect the endpoint. This method is grounded on the fact that electrical conductance relies on the number and mobility of ions. For instance, consider titrating strong acid HCl with a strong NaOH base. Initially, the HCl in the conductivity vessel conducts electricity due to the presence of hydrogen ions and chloride ions. As NaOH is gradually added from the burette, the fast-moving hydrogen ions are replaced by slower-moving...

When a weak acid such as acetic acid is titrated against a strong base like sodium hydroxide, the initial conductance is relatively low due to the weak dissociation of acetic acid. However, as sodium hydroxide is added to the solution, it reacts with the acetic acid to produce highly ionized sodium acetate, which causes an increase in conductance. Once all the acetic acid has been neutralized, any additional sodium hydroxide introduces fast-moving hydroxyl ions, leading to a sharper increase in...

In titrating a weak acid with a strong base, different calculation methods are applied at various stages. Initially, the pH of a weak acid like acetic acid is calculated using its dissociation constant (Ka) and an ICE table. Upon addition of a strong base such as sodium hydroxide, a buffer forms, and its pH is determined using the Henderson-Hasselbalch equation. As more base is added and the titration reaches the halfway point, the pH becomes equal to the pKa of the acid, indicating equal...