Organic Chemistry Questions and Short Answers

There are three types of Van der Waal’s force- Keesom Forces, Debye forces, and London Dispersion forces. Amongst the three types, the London Dispersion forces are the weakest interactions.

The van der Waal forces of interactions are weak intermolecular forces. For the atoms or molecules show these interactions only under certain conditions -

1) Distance- van der Waal forces mainly depend on the distance between the associated molecules. These forces become very weak if the distance between the molecules or atoms is greater. These forces are relatively stronger if the atoms or molecules are grouped closely.

London Dispersion forces are seen in all the atoms and the molecules; however, it is the exclusive force binding nonpolar molecules. Nonpolar molecules are made of two or more atoms, and the electronegativity between two atoms in a covalent bond is less than 0.5. Therefore, no charges are separated to create poles in nonpolar molecules or atoms. Despite not having poles, nonpolar molecules interact using a weak force of attraction known as the London Forces.

Carbon's nondiscriminatory nature to form bonds with itself and other elements has led to a wide variety of small and large organic compounds. Carbon-hydrogen compounds called hydrocarbons are mostly inert; however, carbon with other elements (N, O, S, halogen) form functional groups, the reactive part of the molecule. The functional group part of the molecule is where chemical transformations occur. Some organic compounds can have more than one functional group.

Polar molecules show Keesom forces. Polar molecules have heteroatoms that differ in electronegativity values such that the electronegativity difference between the two atoms in a polar covalent bond is greater than 0.5 but less than 1.7. For example, HF, HCl, R-OH, etc.

Keesom forces occur in polar molecules where the atoms have a considerable electronegativity difference, resulting in the charge separation and formation of positive and negative poles. The negative pole of one molecule electrostatically interacts with the positive pole of the neighboring molecule. Consequently, all the polar molecules in the medium try to orient their dipoles to be in alignment for such electrostatic interactions.

A carbocation is a positively charged, electron-deficient ion of carbon with only 6 valence electrons from the preferred 8 for covalent bonding. Therefore, it acts as an electron-accepting reactive intermediate in many organic reactions.

After accepting two electrons, it can transform from a less stable to a more stable uncharged molecule.