Final answer:
Both plant extracts are suitable to be used as pH indicators because they exhibit color changes in response to acids and bases, which is the fundamental property required of a pH indicator. Option a.
Step-by-step explanation:
The color change in pH indicators in response to acids and bases is what makes them suitable for estimating the pH of a solution. These indicators can be both synthetic and naturally occurring. Thus, the correct answer to whether both plant extracts are suitable to be used as pH indicators is a) Yes, because they change color in the presence of acids and bases.
Examples of natural indicators include red cabbage juice and Hydrangea macrophylla flowers, which change colors depending on the pH. Effective indicators must exhibit a color change that is easily detected, rapid, and should not react with the substance being titrated. Additionally, they should have a pKin within one pH unit of the expected pH at the equivalence point of the titration for minimization of errors.