Question

Which of the following gases is likely to be the least soluble in water? CO, O2, NO, HCN

Answer 1

The rule for a solute to dissolve is "like dissolves like" i.e polar solute are more soluble in polar solvent and vice versa.

Now water is a polar solvent since it has a charge separation between the Oxygen and Hydrogen atoms.

Hence the solute who have charge separation between atoms or who are polar are soluble in it.

Hence among all the 4 gases, O2 is least solubleb in water as it has no dipole moment.

But we all know that the maximum constituent of water is O2. That is due to pressure. When pressure is applied, the gaseous O2 molecule form H- bonding with water molecules.

On the other hand, the other gases in the option are soluble in water without applying any pressure. Because their polar ends easily get attracted towards the polar ends of water, hence more soluble.