Polarity — মেরুকতা
Polarity arises when shared electrons sit closer to one end of a bond or molecule, giving it positive and negative poles.
Definition
Polarity appears when a bond's shared electrons are pulled closer to one atom than to the other, usually because of an electronegativity difference. The electron-rich end turns slightly negative and the other end slightly positive, making a dipole. If the difference is large, the bond behaves close to ionic; if zero or tiny, as in or , it stays nonpolar. Water is the classic polar molecule: its bent shape means the two O–H dipoles cannot cancel, which is why salt, sugar and glucose powder dissolve in it so happily.
For example
Because water is polar and oil is not, mustard oil floats as separate beads on your curry; soap cleans by sending one polar end to grab water and one nonpolar end to grab grease.