Gas solubility in water

Jahne B., Heinz G., and Dietrich W.E. (1987) Measurement of the diffusion coefficients of sparingly soluble gases in water. /. Geophys. Res. 92, 10767-10776. 

The solution or suspension is mixed with a nongaseous fluid (generally a compressed gas). It is suggested that carbon dioxide is a suitable compressible fluid, since it does not solubilize most of the drugs and is also one of the most soluble gases in water. 

The presence of some water-soluble gases in water, for example, CO3, O3, HjS is undesirable since they cause corrosion of metallic and concrete components of the systems used in water technology and industry. Thus, water degassing is one of the most efficient anticorrosion measures. This process is also necessary for feed waters used in boilers. For water degassing both thermal and chemical procedures are required. 

In the case of three-phase equilibria, it is also necessary to account for the solubility of hydrocarbon gases in water. This solubility is proportional to the partial pressure of the hydrocarbon or, more precisely, to its partial fugacity in the vapor phase. The relation which ties the solubility expressed in mole fraction to the fugacity is the following ... 

Solubility of hydrocarbon gases in water expressed as Henry s constants. 

Solubility of gases in water decreases with increasing temperature. 

An analogous law was established in 1803 by W. Henry for the solubilities of gases in water hence, this expression is called the Henry isotherm. The adsorption coefficient B (units dmVmol) depends on the heat of adsorption B = B° e,xp(q RT). The Henry isotherm is valid for low surface coverages (e.g., at 9 < 0.1). 

The solubility of nearly all gases in water decreases as the temperature is increased. Furthermore, the solubility of a gas increases with the partial pressure of the gas above the surface of a liquid solution, expressed as Henry s Law ... 

FIGU RE 6.3 Solubility of noble gases in water as a function of polarizability. 

Explain in terms of molecular structure the following trend in solubilities of the gases in water C2H2 > > C2H4 > C2H6. How does the trend in solubility reflect other chemical properties ... 

Table 5.4 lists a few Henry s law constants, which relate to the solubility of gases in water. 

Two recent events allow a more detailed picture of the solubility of hydrogen, nitrogen, oxygen, and the noble gases in water to be given, than could have been given even a year ago. First, a careful compilation and evaluation of the gas solubility values in water at a gas partial pressure of one atm between the temperatures of 273.15 and about 350 K was carried out by Battino [1 —5]. Second, an experimental study of the solubility of the noble gases in water at moderate pressures and at temperatures up to 561 K by a new method was reported by Potter and Clynne [6J. 

---