Final answer:
A solution with gas bubbles is an improper choice for a simple flotation procedure because it indicates the mixture is not homogeneous, which can affect the procedure's reliability by altering buoyancy and separation.
Step-by-step explanation:
The solution that is not ideal to use for a simple flotation procedure is one where bubbles of gas are observed within the liquid. This indicates that the mixture is not homogeneous and therefore not a true solution. In flotation procedures, a homogeneous solution is necessary to ensure consistent properties throughout the liquid, which is critical for the accuracy and reliability of the results. Bubbles can interfere with the flotation process, affecting the buoyancy and separation of substances.