Henry’s Law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid, provided the temperature remains constant. Mathematically, it can be expressed as:
C = KH×P
- C is the concentration of the dissolved gas in the liquid.
- KH is Henry’s Law constant.
- P is the partial pressure of the gas above the liquid.
Significance of Henry’s Law constant (KH): The value of KH provides a measure of how soluble a particular gas is in a particular liquid at a given temperature. A higher value of KH indicates that the gas is less soluble in the liquid, while a lower value of KH indicates greater solubility. The unit of KH varies depending on the way solubility is measured. It can be in terms of mol/L·atm, g/L·atm, or other suitable units.
Given the information that hydrogen is more soluble in water than helium at the same temperature, hydrogen will have a lower value of KH compared to helium. This is because a higher solubility corresponds to a lower KH (as mentioned earlier). Hence, less soluble helium will have a higher value of KH.
In summary, the gas with the higher KH value is less soluble in the liquid. In this case, helium is less soluble than hydrogen, so it has a higher KH.