I’d call both nonpolar
(1) look at electronegativities to determine if the bonds are polar
(2) look for symmetry. a molecule with polar bonds is NON polar if it is symmetric!
here’s a table of EN
when it comes groups.. like -OH.. things get a bit more complicated. Oone of the simpliest approximations is
in -O-H.. the are 2 O bonds (2×3.44) & 1 H bond (1×2.20) for a total EN of (2*3.44+1×2.20)/3 = 3.03
The rules of thumb for determining the type of bond go..
if ΔEN < 0.5, the bond is nonpolar covalent
if 0.5 < ΔEN < 1.5, the bond is polar covalent
if 1.5 < ΔEN < 2.0 AND no metal is present, the bond is polar covalent
if 1.5 < ΔEN < 2.0 AND a metal is present, the bond is ionic
if 2.0 < ΔEN, the bond is ionic
and again.. those are rules of thumb
in Be(OH)2.. .the Be-OH bond had ΔEN = 3.03 – 1.57 = 1.46… so this should be a polar covalent bond
in CF3Cl, ΔEN between C and F = 3.98 – 2.55 = 1.43.. ΔEN between C and Cl is 3.16 – 2.55 = 0.61.. and all the bonds are polar covalent
as to symmetry…
it turns out Be(OH)2 is in fact a linear molecule.. H-O-Be-O-H.. so it has "electronic symmetry" and the different areas of high electron density cancel out.
CF3Cl is also a symmetric molecule. it’s shape is tetrahedron. and therefore is non polar..
now both molecules will actually have areas of partial charges.. F has a higher EN than Cl so it will withdraw slightly more electron density from the carbon than the Cl will. But what we’re doing here is looking at a broad range of values and drawing lines in the sand and saying if you’re on this side your polar and on that side your not. Get it? I think CF3Cl is on the non polar side of that line.
in any case..
polar molecules must have polar bonds
polar molecules cannot have electronic symmetry.
how about that.. 3 of the usual answerers here on YA. 3 different answers.
CF3Cl is polar because this forms a tetrahedral molecule, but because you have different substituents, there is a net dipole moment in the molecule.
I would consider Be(OH)2 to be an ionic compound. I don’t think ionic compounds are generally considered to be either polar or non-polar.
Be(OH)2 is linear thus canceling any effect of polar bonds
CF3Cl is tetrahedral with one corner occupied by F which is more electronegative than the Cl’s
so it is somewhat polar