An overview on Properties of Polar Covalent Compounds

When atoms having differing electronegativities share electrons within a covalent link, the result is a formation of polar covalent bond. 

Consider the molecule of hydrogen chloride (HCl). In order to generate an inert gas electron configuration in the molecule, each atom in HCl requires one extra electron. The electronegativity of chlorine is stronger than that of hydrogen, but the chlorine atom’s attraction for electrons is insufficient to take one electron from hydrogen. As a result, within a polar covalent bond, the bonding electrons in HCl are shared unequally. Even though the shared electron pair is related with chlorine to a greater extent than hydrogen, the molecule is represented by the standard Lewis structure.

Because of the unequal sharing of the bonding pair, the chlorine atom gets a partial negative charge and the hydrogen atom gets a partial positive charge. These fractional charges are represented by the symbol δ.

The various forms of covalent bonds are mostly determined by electronegativity of the compound. An atom’s tendency to attract a shared pair of electrons to itself is known as electronegativity. It doesn’t have any units. A polar chemical bond is defined as a chemical bond formed between two atoms in a molecule with an electronegativity difference.

A polar bond is a covalent link formed between two atoms in which the electrons are unequally distributed. This results in a tiny electrical dipole moment in the molecule, with one end slightly positive and the other slightly negative. Electric dipoles have a charge that is less than a full unit charge, hence they are referred to as partial charges and are represented by delta plus (+) and delta negative (-). Molecules having polar covalent bonds interact with dipoles in other molecules because positive and negative charges are separated in the bond. Intermolecular forces between the molecules are created as a result of this dipole-dipole interaction.

Properties of polar covalent bond

• • Physical state: Because of the stronger force of interactions, these chemicals can exist as solids.
  • Solubility: In polar solvents like water, they are very soluble.

• Conductivity: Because of the mobility of ions, they conduct electricity in the solution state

• Melting points and Boiling points: The melting and boiling temperatures of these compounds are higher than those of non-polar compounds.

Melting points and Boiling points-

Since the interactions between molecules are easily overcome, they have low melting and boiling points. Because there are no free costs to move, they do not conduct electricity. The melting temperatures of some covalent molecular compounds are higher than expected.

Covalent compounds have low melting and boiling temperatures because only a small amount of heat (energy) is required to disrupt these weak intermolecular connections. Covalent compounds have low melting and boiling points due to weak intermolecular forces of attraction and weak van der waal forces.

Conductivity-

Although covalent interactions between atoms are fairly strong, intermolecular forces, or attraction between molecules/compounds, can be quite modest. Because covalent compounds do not consist of the charged particles capable of transferring electrons, they do not cause electricity. Conduction.

In their molten state, polar covalent molecules conduct electricity. Most covalent compounds are poor carriers of electricity, however a few polar covalent compounds, such as water and liquid ammonia, can conduct electricity due to self-ionization.

Solubility-

In polar liquids, polar substances are soluble. Covalent chemicals are soluble in non-polar solvents like ether and ionic compounds are soluble in polar solvents like water because they are less polar or nonpolar (H2O).

The like always dissolves like rule is used in covalent solubility. This means that compounds with similar polarities will dissolve in one other. Furthermore, compounds having polarities that differ from one another will be insoluble in one another.

CONCLUSION-

When electrons are shared between atoms and attracted by the nuclei of both atoms, covalent bonds occur. The electrons in pure covalent bonds are shared evenly. The electrons are shared unequally in polar covalent connections because one atom exerts a stronger force of attraction on the electrons than the other. Electronegativity may be considered as an atom’s ability to attract a pair of electrons in a chemical connection. The polarity of a bond is determined by the difference in electronegativity between two atoms.