How can the pH of an organic acid be determined?

Determining the pH of an organic acid involves assessing the acidity of the solution, which can be effectively done with a pH indicator. A pH indicator is a substance that changes color at a particular pH range, allowing for a visual assessment of the acidity or basicity of the solution. By adding a pH indicator to the organic acid solution and comparing the resulting color to a standard pH scale, one can accurately gauge the pH level.

This method is particularly useful because it provides immediate visual feedback regarding the acidic strength of the solution. In contrast, measuring the density of the solution does not directly correlate with pH, as density is influenced by both concentration and temperature, not just acidity. Heating the solution until it evaporates would alter the composition of the solution and does not provide any information about the pH. Observing the reaction of the organic acid with a metal might indicate acidity through the release of hydrogen gas, but it would not offer a quantitative measure of pH. Thus, using a pH indicator is the most reliable and direct method to determine the pH of an organic acid.