MCQ Detailed View

In physical chemistry, understanding interatomic forces is important for studying molecular structure and bonding. When two hydrogen atoms approach each other, two types of forces act simultaneously: attractive forces (due to electron-proton interactions) and repulsive forces (due to electron-electron and nucleus-nucleus repulsion).

The distance at which these attractive forces exactly overcome the repulsive forces is known as the equilibrium bond distance. For a hydrogen molecule (H₂), this distance is 75.4 picometers (pm). At this specific separation, the potential energy of the system is minimized, and the bond between the hydrogen atoms is most stable.

Other options are close but slightly incorrect. Precise measurements show that 75.4 pm is the accepted equilibrium bond distance for H₂, reflecting the balance between electrostatic attraction and repulsion. Understanding this distance helps explain bond lengths, bond energies, and molecular stability in chemistry.

This concept is fundamental in physical chemistry, quantum chemistry, and molecular physics. It helps students calculate potential energy curves, understand van der Waals interactions, and predict chemical behavior of molecules. Knowledge of equilibrium distances also supports the study of vibrational motion, spectroscopy, and thermodynamic properties of molecules.

By knowing that the equilibrium distance for hydrogen is 75.4 pm, students can understand how molecular interactions influence physical properties, such as boiling and melting points, molecular geometry, and reaction dynamics.

Thus, the distance at which attractive forces overcome repulsive forces for hydrogen atoms is 75.4 pm, highlighting a key principle in molecular chemistry and interatomic bonding.