Solubility of CO2andN2O in certain Solvents

Solubility of $C{O}_{2}$ and ${N}_{2}O$ in Twelve Solvents, 18\ifmmode^\circ\else\textdegree\fi{} to 36\ifmmode^\circ\else\textdegree\fi{} $C$.---Since according to the Lewis-Langmuir theory these two gases have similar molecular structures, it is of interest to compare their solubilities in various liquids. In the method adopted, the air was thoroughly removed from the solvent by boiling and then the gas to be tested, having been carefully purified with the help of liquid air, was admitted and shaken up with the solvent until no further solution took place. Observations accurate to better than one per cent. were made for water, acetone, acetic acid, methyl alcohol, pyridine, ethyl alcohol, benzaldehyde, aniline, amyl acetate, ethylene bromide, isoamyl alcohol, and chloroform. Taken in this order, the ratio of the solubility of C${\mathrm{O}}_{2}$ to that of ${\mathrm{N}}_{2}$O decreases regularly from 1.34 (20\ifmmode^\circ\else\textdegree\fi{}) for water to 0.66 for chloroform. This range of variation is small, and moreover the ratio is nearly constant for each solvent, changing less than one per cent. for six solvents, and not more than three per cent. for the others except chloroform and acetone. Also, the temperature coefficient ($\frac{\mathrm{ds}}{\mathrm{sdT}}$) is in most cases nearly the same for the two gases. It is always negative, the solubility decreasing with increasing temperature.Discussion of Suggested Solubility Relations, for Gases in Liquids.---Raoult's law does not hold for the solubility of gases in liquids. It is also shown that there is little, if any, relation between solubility and the difference between the internal or cohesion pressures of solvent and solute. However, the ratio of the solubilities of C${\mathrm{O}}_{2}$ and ${\mathrm{N}}_{2}$O varies regularly with the dielectric constant of the solvent, and since this constant may be taken as an index of the polarity of the solvent and since C${\mathrm{O}}_{2}$ is more active chemically and therefore has stronger polarity than ${\mathrm{N}}_{2}$O, this result suggests that polarity may be an important factor in determining the relative solubility of gases in liquids.