Hydrogen gas is sparingly soluble in water. At 25 degrees Celsius and a partial pressure of one atmosphere, hydrogen gas has a mole fraction solubility of 0.00001411 in pure water. A liter of water dissolves about 0.00078 moles of hydrogen at a partial pressure of one atmosphere.
Because hydrogen gas is a non-polar molecule, it does not readily form hydrogen bonds with water molecules, making it not very soluble in water. The solubility of hydrogen in water is comparable to the solubility of nitrogen or oxygen gas, both of which are also non-polar. Polar gasses, such as carbon dioxide, exhibit solubility values 100 times greater than that of hydrogen.