If CO2 is a non polar covalent bond why can it dissolve in water.?

Question

Is it polar or nonpolar?my notes tell me it's nonpolar and that only polar covalent bonds dissolve in water.
I say it's nonpolar. It dissolves in water. I'm confussed on this one. Can anyone explain. Thanks

Answer 1

CO2 is a non polar compound. Under the right pressure and temperature it will react with water molecules like this:
CO2 + H2O -> H2CO3
that is a weak acid so it is partially ionized :
H2CO3 <-> H+ + HCO3-
These three forms are in equilibrium.
HCO3- is an anion, soluble in the water.
When the temperature increases or the pressure diminishes, the H2CO3- Will react with the water that surrounds it, like this:
H2CO3 + H2O -> CO2 + 2H2O
and the CO2 will became gas again and will make the bubbles in the "champagne".
This is how our circulatory system releases toxic CO2 from the cells to the lungs via blood erythrocytes.

Answer 2

First of all, as Strange_Days very correctly commented, the bonds are polar but the molecule is not because the dipole moments of the two polar bonds cancel each other.

CO2 is a nonpolar molecule.
Some nonpolar gases can dissolve in water, though to a small degree, due to induced dipole-dipole interactions. That's how some hydrates like with noble gases or methane form.
Also don't forget that O2 is also nonpolar but still dissolves at levels enough to sustain marine life.

The solubility of a gas in water increases if it can react/dissociate in water. Vovozinha very nicely explained how dissolved CO2 froms H2CO3 which dissociates further to various ions.

It also depends on factors such as temperature, pressure (and the ionic strength of a solution if we are not talking about pure water).

Answer 3

In CO2, the two C=O double bonds are definitely polar (high difference in electronegativity between C and O), however, it has a linear shape, which "cancels out" the polarity.
<--+ +-->
O = C = O

The dipoles are shown above as +-->, and the arrow shows the direction of electron withdrawal. Like vectors, the two dipoles "add" together to make the overall polarity 0, thus it cannot be dissolved in water (at least not that much).

Answer 4

CO2 is nonpolar, because its shape is linear. Water is polar, because of the covalent bonds with hydrogen, so CO2 doesn't dissolve in water. Nonpolar dissolves in nonpolar, polar dissolves in polar.

Answer 5

The bonds don't break when it "dissolves" in water. The gas diffuses into the water, but it is still CO2.

Answer 6

Remember this rule, "like dissolves like". Polar dissolves polar and non polar dissolves non polar. Water is polar and carbon dioxide is non polar so water cannot dissolve it.

Water is polar and oil is not, this is why they do not mix, and they cannot dissolve each other.

Answer 7

CO2 is only slightly soluble in water at regular temperature and pressure. If you put CO2 under immense pressure, it will dissolve completely. (Soft drink, anyone?)

Answer 8

Open a soda, you will hear it not dissolving.