GENERAL KNOWLEDGE

Detailed explanation-1: -Hydrocarbons have very weak intermolecular forces called dispersion forces. Intermolecular forces hold molecules together. Imagine the forces are like double sided tape and the molecules are like pieces of paper on each side.

Detailed explanation-2: -However, the larger hydrocarbons, pentane (C5H12), hexane (C6H14), etc are liquids at room temperature because they are large enough for the London dispersion force to be strong enough to hold them together. For the forces to be strong enough to make the molecules solid, the hydrocarbons must have at least 17 carbons.

Detailed explanation-3: -For hydrocarbons and other non-polar molecules which lack strong dipoles, these dispersion forces are really the only attractive forces between molecules. Since the dipoles are weak and transient, they depend on contact between molecules – which means that the forces increase with surface area.

Detailed explanation-4: -Hydrocarbons exhibit only dispersion forces. Stronger intermolecular forces usually correlate with higher boiling points. Boiling point generally increases with molecular weight due to increased strength of dispersion forces.

Detailed explanation-5: -The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. This force is sometimes called an induced dipole-induced dipole attraction.