Polar. Oxygen's electronegativity is 3.44 while Chlorine's is 3.16. Since the valance electrons are not shared equally, we look at electronegativity. It is polar, and oxygen is the atom closer to the negative side.
CH3CN, Acetonitrile, is a polar molecule. With the triple bond between C and N, a negative charge weighs to the Nitrogen, while on the other "side" of the molecule the Hydrogen atoms tend to a...