In what type of solutions can pH be measured?

pH measurement is fundamentally based on the concentration of hydrogen ions in a solution, which is generally most accurately assessed in water-based solutions. Water acts as a universal solvent, allowing for the complete dissociation of acids and bases, enabling a clear evaluation of acidity or alkalinity through pH levels.

In a water-based solution, pH can be reliably determined since the ionization of most acids and bases occurs in this medium. This is due to the high polarity of water molecules, which facilitates the dissociation of solutes.

While alcohol-based and oil-based solutions may exist, they do not provide the same reliable environment for pH measurement as water-based solutions do. In these other types of solutions, the ionization of acidic or basic substances is either limited or not conducive to accurate pH readings. Acidic solutions, while they do have a pH value, are a specific example of water-based solutions and do not encompass the entirety of the environments where pH can be measured. Thus, the best and most comprehensive answer is that pH can be effectively measured in water-based solutions.