Question

What are examples of dipoles?

Answer 1

Hint: A dipole is a pair of charges which are equal in magnitude and opposite in charge that are separated by a distance. Dipoles are present in molecules when there is a separation of charges or we can say, the constituent atoms possess an electric charge. Electric charge is present on the atoms of molecules that contain ionic bonds or polar covalent bonds. Hence, the ionic and polar covalent molecules can be considered as dipoles.

Complete answer:
We know that the atoms and the compound are naturally neutral. A dipole is said to be generated in the compound when there is a separation of charges in a molecule.
We know that in an ionic compound, the constituents are present as ions which carry either positive or negative charge. Hence, as there is a bond between the charges. Hence, as these opposite charges are located at a distance from each other, a dipole is said to be generated in them. Hence, most ionic compounds contain dipole moments.
The examples of dipoles are Hydrochloric acid $ \;HCl $ , Sodium chloride $ \;NaCl $ , Acetic acid $ CH_3COOH $ etc.
Now, we know that ionic compounds are formed when the electronegativity difference between the constituent atoms is $ \;1.8 $ .
If the difference is less than $ \;1.8 $ , then a covalent compound is formed. But as there is still an electronegativity difference, the higher electronegative atom will cloud the electron towards itself, creating a partial negative charge on itself, and a partial positive charge on the other atom.
Hence, as there is a separation of charges that are at a small distance from each other, we can say that a dipole is generated in the polar covalent compound.
Hence, the examples of dipoles are water $ H_2O $ , ammonia $ NH_3 $ , etc.

Note:
We should remember that a dipole is a vector quantity. Hence, it depends on the magnitude as well as direction. Hence, even though certain molecules have dipole moments on individual bonds, the overall value of the dipole can be zero if the vector sum of the individual dipoles is zero. For example, even though every bond in carbon tetrachloride $ CCl_4 $ is polar and has a dipole moment, the bonds are arranged in such a way that the vector of any three dipole moment is equal and opposite to the fourth dipole, and hence the molecule as a whole is non-polar.