Indiana Pesticide Applicator Core Practice Exam

When is a substance said to be in solution?

1. When it is combined with solid particles

2. When it is dissolved in a liquid

3. When it is mixed with other solids

4. When it is combined without a chemical reaction

The correct answer is: When it is dissolved in a liquid

A substance is said to be in solution when it is dissolved in a liquid. This process involves a solute (the substance being dissolved) interacting with a solvent (the liquid) to form a homogeneous mixture at the molecular level. The characteristics of a solution include uniformity and clarity, as the solute becomes evenly distributed throughout the solvent. In this context, it's important to note that combining a substance with solid particles doesn't necessarily create a solution, as the solid particles may remain distinct rather than dissolve. Similarly, mixing with other solids technically does not lead to a solution, as solutions specifically involve a solute dissolving in a solvent. Lastly, combining substances without a chemical reaction refers more to physical mixing than the dissolution process that defines a solution. Thus, the answer highlighting dissolution in a liquid captures the essence of what constitutes a solution.