Answer:
It will become polar.
Explanation:
Look the image below. I know it's terrible, but I'll explain it:
ΔE is the electronegativity. The higher is the ΔE of a substance, the more it can attracts electrons.
Cl has more electronegativity than C and H. But it has, of course, the same amount of another Cl.
So, when we have a tetrahedral space disposition such as in the left draw, all the Cl cancels the others eletrostatic force. However, when we replace one Cl for H, then we will have a dipole moment pointing to the Cl who face the Hydrogen, as the right draw. The appearance of a resulting dipole indicates the existence of a polar compound.
