Polarity

Molecules are either polar or nonpolar. Polarity is determined by the distribution of electrons throughout the molecule. Polar molecules are those which have an even distribution of electrons (charges) throughout the molecule, while non-polar molecules are those which have an uneven distribution of electrons.

Carbonic Acid is a polar molecule. In the diagram below, it is seen that one end of the molecule is much more negatively charged than the other, as one end includes two positively charged hydrogen and two negatively charged oxygen, while the other only includes one negatively charged oxygen. Therefore, the electron distribution of the atom is uneven, making it a polar molecule.

The bonds between the atoms within molecules are also considered either polar or non-polar. Polar bonds are those between any atom and another atom with a different Electronegativity Value. Non-polar bonds are those between two of the same atoms. All of the bonds in the Carbonic Acid molecule are polar covalent bonds. The arrows in the above diagram show the flow of the energy from the atom with the higher electronegativity value to that with the lower, in each of the bonds. Because all the bonds are polar covalent, each bond has a corresponding arrow.

The bonds between Carbon and Oxygen are represented by taking the absolute value of the difference between the Electronegativity Values of Carbon and Oxygen. This value is 1, which makes the bonds moderately covalent.

The bonds between Oxygen and Hydrogen are represented by taking the absolute value of the difference between the Electronegativity Values of Oxygen and Hydrogen. This value is 1.3, which makes the bonds barely covalent.