Question

Polarity of molecules. Provide some examples of polar and non-polar molecules.

Answer 1

Polarity in chemistry refers to the distribution of electric charge around atoms, chemical groups, or molecules.

Polar molecules occur when there is an electronegativity difference between the bonded atoms. On the other hand, nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out.

Examples of polar molecules include:

• Water - $H_2O$
• Ammonia - $NH_3$
• Sulfur dioxide - $SO_2$
• Hydrogen sulfide - $H_2S$
• Ethanol - $C_2H_6O$

Examples of nonpolar molecules include:

• Noble gasses: $He, Ar, Ne, Xe$ (These are atoms, not technically molecules.)
• Any of the homouclear diatomic elements: $H_2, O_2, Cl_2,N_2$  (These are truly nonpolar molecules.)
• Carbon dioxide - $CO_2$
• Benzene - $C_6H_6$
• Carbon tetrachloride - $CCl_4$
• Methane - $CH_4$