pHmérést

pHmérést is a hypothetical substance that, if it existed, would be a pH indicator with a unique property: it would change color not based on the concentration of hydrogen ions (H+) in a solution, but rather based on the concentration of hydroxide ions (OH-). This is in contrast to most pH indicators, which change color in response to the hydrogen ion concentration.

The concept of pHmérést was proposed as a thought experiment to illustrate the difference between acidity and basicity. In a solution, the concentration of hydrogen ions and hydroxide ions are related by the water dissociation constant (Kw), which is a constant value at a given temperature. Therefore, measuring the concentration of one ion provides information about the concentration of the other.

If pHmérést existed, it would change color in a manner opposite to that of traditional pH indicators. For example, a solution that is strongly acidic (high H+ concentration) would appear basic (high OH- concentration) when viewed through pHmérést. This would make it a useful tool for educational purposes, as it would help students and researchers understand the relationship between acidity and basicity more intuitively.

However, it is important to note that pHmérést is purely hypothetical. No such substance has been discovered or synthesized, and it is unlikely that one will be in the near future due to the fundamental nature of pH and the behavior of ions in solution. The concept of pHmérést serves as a useful mental exercise for understanding pH and the behavior of ions in solution, rather than a practical tool for chemical analysis.