It may be too late, but when it becomes polarised, the electrons become unbalanced, either due to a permenant dipole, or an instantaneous one. This leads the particle to attract, and cause dipoles in other compounds.
Answered Mon 23rd September, 2013 @ 14:47 by NumNub
Chlorine has greater electronegativity then many other atoms and is able to attract electrons. If a chlorine atom comes close to a non-polr molecule then it will attract the electrons near to it. This will create an imbalance of electron distribution in the nearby molecule. This results in there being a charge difference or charge inequality (or a dipole) in the neighbouring molecule -i.e it is polarised :-) x