Question

Why is styrene and propene non-polar?

Answer 1

Well `C-C` and `C-H` are very non-polar bonds......

Explanation:

For a `C-H` bond there is only marginal charge separation between the bound atoms; for a `C-C` there should be no charge separation, as the bound atoms have no difference in electronegativity. For ethylene, `H_2C=CH_2`, even if there were bond polarity, the molecular dipole would be zero because of the symmetry. Maybe styrene, `C_6H_5CH=CH_2` should be a little more polar, however, the difference should be marginal.

Anyway, a styrene monomer is not going to stick around too long before it polymerizes.