Question

Why O2 and CO2 are soluble in water? Can you please explain?

Answer 1

CO2 is more soluable in water tha O2. CO2 reacts with the water molecules as follows and therefore is readily soluable in water.

CO₂(aq) + H₂O H₂CO₃(aq)

The carbonic acid dissociates to form H+ and CO3 ^2-.

H₂CO₃(aq) H⁺(aq) + HCO₃^-(aq)
HCO₃^-(aq) H⁺(aq) + CO₃^2-(aq)

Also, it is easier for CO2 to dissolve in water as the oxygen ends of the molecule is very very slightly polar.

In the case of oxygen, it enters the surface of water as a result of diffusion, in the case of still water, or mixin, in the case of running water. This is a very slow process. Once O2 enters the surface of water, it is surrounded by water molecules.