What does Henry's Law state about a gas in contact with a liquid?

Henry's Law states that at a constant temperature, the amount of gas that dissolves in a liquid is directly proportional to the partial pressure of that gas above the liquid. This means that when a gas is in contact with a liquid, an equilibrium is established where the gas will enter the liquid until a specific concentration is reached, depending on the pressure exerted by the gas.

When considering the context of diving and human physiology, this principle is critically important. For example, as a diver descends deeper into water, the pressure increases, leading to a greater amount of gases like nitrogen dissolving into the body's tissues. Understanding this law is essential for managing dive-related conditions, such as decompression sickness.

In contrast, the other options do not accurately reflect the essence of Henry's Law. While gas evaporation can occur, it is not guaranteed and does not represent the interaction as outlined by Henry's Law. The gas remaining unchanged fails to recognize the dynamic equilibrium between the gas phase and the dissolved phase. Lastly, the suggestion that a liquid will gasify does not correspond with the law’s focus on gas dissolution. Instead, Henry's Law emphasizes that gases tend to dissolve in liquids under certain pressure conditions.