Question

Why are polar molecules said to have dipoles?

Answer 1

Well, what is a dipole...?

Explanation:

A dipole is a physical separation of positive and negative charge. Given electronegative atoms within a MOLECULE, i.e. atoms that strongly polarize electron density towards themselves, charge separation occurs, and molecular dipoles are formed...

And let us consider a couple of molecular dipoles, say, `HF`, and `H_2O`....both oxygen and fluorine atoms are electronegative with respect to hydrogen....and there is unequal distribution of electronic charge in the molecule...the which we could represent as...`stackrel(+delta)H-stackrel(-delta)F`, or `stackrel(+delta)H_2stackrel(-delta)O`...I leave it to you to look up the molecular dipole moments...