Which of the following molecules is non-polar in nature ?

The question asks which molecule among the given options is non‑polar. The correct choice is SbCl₅. To understand why, we examine the molecular geometry and dipole‑moment cancellation for each compound.

SbCl₅ (antimony pentachloride) has a central antimony atom surrounded by five chlorine atoms. According to VSEPR theory, five electron‑pair domains adopt a trigonal‑bipyramidal arrangement. In this geometry, three Cl atoms lie in an equatorial plane at 120° to each other, and two Cl atoms occupy axial positions 180° apart. Because all Sb–Cl bonds are of equal length and have identical electronegativity differences, the individual bond dipoles are equal in magnitude. The three equatorial bond dipoles cancel each other in the plane, and the two axial bond dipoles are equal in magnitude but point in opposite directions. The vector sum of all five bond dipoles is therefore zero, giving the molecule no net dipole moment—hence it is non‑polar.

For the other choices:

NO₂ (nitrogen dioxide) has a bent shape with a lone electron pair on nitrogen. The two N–O bonds are not symmetrically arranged, so their dipoles do not cancel, making the molecule polar.

POCl₃ (phosphoryl chloride) has a trigonal‑pyramidal geometry due to a lone pair on phosphorus. The asymmetry caused by the lone pair prevents complete cancellation of the P–O and P–Cl bond dipoles, resulting in a polar molecule.

CH₂O (formaldehyde) possesses a trigonal planar structure with the carbon atom double‑bonded to oxygen and single‑bonded to two hydrogens. The C=O bond is highly polar, and the molecule lacks symmetry to offset this dipole, so it is polar as well.

Only SbCl₅ meets the criteria for a non‑polar molecule among the listed options.