Question

What are polar and nonpolar molecules?

Answer 1

In the given question firstly we have to define the facts regarding the polarity and the no polarity and the basic definition. A molecule in which the individual dipoles do not cancel each other and results in a net dipole moment is called a polar molecule. And the vice versa is true for the non polar molecules.

Complete step-by-step answer: The given question statement asks about that which among the given options correctly proves the reason behind ice-melts at a temperature lower than its usual melting point, when the pressure increases.
Polar Molecule:- A molecule in which the individual dipoles do not cancel each other and results in a net dipole moment is called a polar molecule.
In polar molecules there is partial charge on every atom of the molecule and the solution of polar molecules contains some positively charged and some negatively charged ions. Polar molecules are formed by atoms which have different electronegativity.
Example:- ${H_2}O$ , It has a slight positive charge on one side and slight negative charge on the other side. So that’s why it is a polar molecule.
Non-Polar Molecule:- A molecule in which the individual dipoles cancel each other & result in zero net dipole moment is called a nonpolar molecule.
In non-polar molecules there are no partial charges on any atom and no ions in the solution of non-polar molecules. Usually non-polar molecules are formed by the atoms which have almost equal electronegativity.
Example:- ${H_2}$ , it has a net zero dipole moment. So that’s why it is a nonpolar molecule.
Non polar molecules are symmetric with no unshared electrons. Polar molecules are asymmetric, either containing lone pairs of electrons on a central atom or having atoms with different electronegativities bonded.

Note: Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms. A polar molecule with two or more polar bonds must have a geometry which is asymmetric in at least one direction, so that the bond dipoles do not cancel each other.