The following plot shows the potential energy of two Cl atoms as a function of the distance between them. (c) If the Cl₂ molecule is compressed under higher and higher pressure, does the Cl–Cl bond become stronger or weaker?

Key Concepts

Potential Energy Curve

The potential energy curve illustrates how the potential energy of a system changes with the distance between two atoms. In the case of Cl atoms, the curve shows a minimum point where the bond is most stable, indicating the bond energy. As the distance decreases, potential energy decreases until it reaches a minimum, after which it increases sharply, indicating repulsion when atoms are too close.

Bond Strength and Distance

Bond strength is related to the energy required to break a bond. As the interatomic distance decreases, the bond becomes stronger until the equilibrium distance is reached. If the Cl–Cl bond is compressed further, the bond may weaken due to increased repulsion between the electron clouds of the atoms, which can lead to bond breaking if the pressure is excessive.

Effect of Pressure on Molecular Bonds

Applying pressure to a molecule can influence the bond length and strength. In the case of Cl2, increasing pressure can initially strengthen the bond by bringing atoms closer, but excessive pressure may lead to a weakening of the bond due to repulsive forces. Understanding this balance is crucial for predicting molecular behavior under varying conditions.