Chemistry 9

Sulphur Dioxide forms Sulphurous Acid when dissolved in water, thus water acts as a Sulphur Dioxide sponge, and retains the Sulphur Dioxide. Adding to this, Sulphur Dioxide is also soluble (positive dipole moment) in water and thus is also trapped by the water.

A process like collecting the gas over water is thus not possible for SO2.

$\ce{SO2}$ is highly soluble in water, therefore, it cannot be collected over water. The solubilities (g of gas/100 g of water) of the three gases in water at $20^\circ$ C and $1$ atm are as follows:

$\begin{array} {cc} Gas & Solubility \\ \hline \\ \ce{N2} & 0.019 \\ \ce{O2} & 0.043 \\ \ce{SO2} & 11.28 \end{array}$

Extracts from Solubilities of Gases in Water at 293 K

I thinked of atmosphere where nitrogen and oxygen are above water in large quantities whereas SO2 not