Question

The presence of a plane of symmetry in a molecule is a quick way to determine its ________?

1) molecular weight
2) molecular formula
3) molecular structure
4) molecular polarity

Answer 1

The presence of a plane of symmetry in a molecule helps to determine its molecular polarity; symmetric molecules are typically nonpolar, while asymmetric ones with polar bonds tend to be polar. So option ( 4) is correct.

Step-by-step explanation:

The presence of a plane of symmetry in a molecule is a quick way to determine its molecular polarity. A symmetric molecule, where all sides around the central atom are identical and bonded to the same element with no unshared pairs of electrons, is typically nonpolar. For instance, a tetrahedral molecule like methane (CH4) or a trigonal planar molecule like boron trifluoride (BF3) are nonpolar because they have symmetrical structures and the individual bond dipole moments cancel out. On the other hand, molecules that lack symmetry, have polar bonds, and are not symmetric (such as H2S or NH3) tend to be polar because the bond dipole moments do not cancel out, resulting in a net dipole moment.