SSC MTS 2024 PYQ — Question 54

The correct answer is  option 2 i.e. instantaneous dipole moment.

Non-polar molecules, though lacking a permanent dipole moment, can exhibit instantaneous dipole moments. These occur due to temporary fluctuations in the electron cloud around a molecule. At any given instant, electrons may be unevenly distributed, creating a momentary dipole. This temporary dipole can then induce dipoles in nearby molecules, leading to weak attractions called London dispersion forces—a type of van der Waals force. These forces are the primary mode of interaction between non-polar molecules like helium, methane, and nitrogen gas. While weak, these interactions are significant in determining boiling points, melting points, and physical properties of non-polar substances.