Final answer:
The color of a solution can change as a reaction proceeds to completion due to the formation of different-colored products or changes in concentration. Indicators can also change color depending on the pH of the solution.
Step-by-step explanation:
The color of a solution can change as a reaction proceeds to completion. The color change can be due to the formation of a product with a different color, the formation of a gas or precipitate, or a change in the concentration of species in the solution. For example, if a green solution and a colorless solution are mixed, the resulting mixture may have a pale green color. Additionally, the concentration of an indicator solution can affect its perceived color, with higher concentrations of one species resulting in a different color compared to higher concentrations of another species.