What is a common property of plant pigments used in chromatography?

Plant pigments are often soluble in alcohol, making this the correct answer for the question regarding their common property as used in chromatography. In chromatography, a technique frequently employed for separating and identifying substances, the solubility of the pigments in organic solvents like alcohol enables them to be effectively separated based on their polarity and affinity for the stationary and mobile phases.

This solubility is crucial during the chromatography process, as it allows the pigments to dissolve and travel up the chromatography medium, which could be paper or another substance. The degree of separation observed in the resulting chromatogram is dependent on how well each pigment interacts with the solvent and the medium.

In contrast, the other properties listed do not accurately reflect the behavior of plant pigments in chromatography. For example, while some pigments may have inert characteristics under certain conditions, they are generally not stable under heat, and their reactivity with water varies widely rather than being a defining trait.