# Why does gas solubility increase at higher pressure?

##### 1 Answer

From Henry's law (at least, this version),

#s = k_HP_(gas)# ,

where:

#s# is the solubility in#"M"# .#k_H# is the Henry's law constant in#"M/atm"# .#P_(gas)# is the vapor pressure of the gas above the solution.

With **increased** external pressure, the gas above the solution has an **increased** vapor pressure above the solution, since

*That mathematically tells you that the solubility increases in the solution for higher pressures.*

That is,

A more conceptual way of explaining this is that higher pressures means **greater force of collision** between gas particles above the solution (pressure is force per unit area). Therefore, their *average kinetic energy* is **greater**, and their *average speeds* are **greater**.

As a result, they are more likely to knock some of the particles down into the solution, thereby dissolving them.