To determine whether a molecule is polar or non-polar, we need to consider the symmetry of the molecule and the distribution of electrons. A polar molecule has an uneven distribution of electron density, resulting in a dipole moment. A non-polar molecule has an even distribution of electrons. - CO (carbon dioxide) is a linear molecule, and both C=O bonds are identical in polarity. Due to the symmetry of the molecule, the dipoles cancel each other out, making CO a non-polar molecule. - H O (water) is a bent molecule with a significant dipole moment. The oxygen atom is more electronegative than hydrogen, and the bent shape causes the dipoles to not cancel out, making water a polar molecule. - CH Cl (chloromethane) is a polar molecule because the C-Cl bond is polar, and the molecule is not symmetrical, resulting in a net dipole moment. Thus, CO is the only non-polar molecule among the choices.