Question

the intermolecular interactions between pentane ($c_5h_{12}$) molecules arise from

• dipole-dipole forces.
• ion-dipole interactions.
• hydrogen bonding.
• london dispersion forces.
• carbon-carbon bonds.

Explanation:

Pentane ($\ce{C5H12}$) is a non - polar molecule composed of carbon and hydrogen atoms. Dipole - dipole forces occur between polar molecules, so pentane does not have dipole - dipole interactions. Ion - dipole interactions require the presence of ions and polar molecules, and pentane is neutral and non - polar, so this is not applicable. Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (such as O, N, F) and interacts with another electronegative atom; pentane has no such structure. Carbon - carbon bonds are intramolecular bonds, not intermolecular forces. London dispersion forces are the intermolecular forces that exist between all molecules, especially non - polar molecules, and they arise from temporary fluctuations in electron distribution. So the intermolecular interactions between pentane molecules are London dispersion forces.

Answer:

London dispersion forces.