<h2>Strength when Intermolecular Forces Increase </h2>
When the strength of intermolecular forces increases then boiling point, melting point, viscosity, surface tension also increases and vapor pressure decreases. With the increase of intermolecular forces B.P, M.P, viscosity and surface tension increases because strong intermolecular forces require more energy to break.
For this purpose energy is provided in the form of heat energy. Therefore, the ones which have stronger bonds will have a higher B.P, M.P, viscosity and surface tension. When the intermolecular forces are strong then the substances are tightly held together so the vapor pressure will be low and it will be difficult to vaporize.
1. Melting point is the temperature at which the solid turns to liquid. In order to reach this point, the intermolecular forces of the solid must be broken so that it would incorporate the molecular arrangement of a liquid.<em> So, the stronger the intermolecular forces, the greater the energy which consequently leads to higher melting points.</em>
2. Vapor pressure is the pressure exerted by the gas above its solid or liquid substance. It is closely related to volatility, which is the ability of the substance to convert from liquid to gas at a certain temperature. <em>The stronger the intermolecular force, the less volatile the substance is which is manifested in increasing vapor pressure.</em>
3. Boiling point has the same concept as melting point, but the change is from liquid to gas. <em>So, the stronger the intermolecular forces, the greater the energy which consequently leads to higher boiling points.</em>
4. Viscosity is the ease of fluidity. Solids, which have stronger intermolecular forces are not viscous at all. <em>So, the stronger the intermolecular forces, the viscosity decreases.</em>
5. Surface tension is the force the substance exerts near its surface or interface. <em>The stronger the intermolecular force, the stronger the surface tension. </em>
