What is the fundamental law that governs all breath testing?

Henry's Law is the correct answer because it describes the behavior of gases when they come into contact with liquids, which is essential for breath testing such as that performed by the Intoxilyzer 8000. This law states that the amount of gas that dissolves in a liquid at a given temperature is proportional to the partial pressure of that gas above the liquid. In the context of breath alcohol testing, when a person exhales, the alcohol in their breath is in equilibrium with the alcohol in their blood. The measurement of the concentration of alcohol in the breath correlates with the concentration in the blood due to Henry's Law.

Understanding this principle is crucial for interpreting breath alcohol results accurately, as it ensures that the breath sample provides reliable evidence of blood alcohol content. Other laws, such as Boyle's Law, Charles's Law, and Avogadro's Law, pertain to different aspects of gas behavior and do not specifically govern the relationship between the concentration of alcohol in the breath and in the blood, making Henry's Law the fundamental law for breath testing.