Question

What causes bond polarity?

Answer 1

For example, hydrochloric acid, water, etc are the example of compounds having a polar bond, so we can tell the polarity of the bonds is created due to the nature of the atoms joining the bond.

Complete answer:
There are two types of compounds, known as polar compounds are non-polar compounds. These are based on the type of bond present in the compound. If the compound has polar bonds then it is known as a polar molecule, and if the molecule has a nonpolar molecule then it is known as a non-polar compound.
The polarity in the molecule is due to the atoms present in it. When the two atoms joining the bond have a large difference in the electronegativity then the bond becomes polar. The electrons joining the atoms will shift a little towards the more electronegative atom and the more electronegative atom will have a slight negative charge while the less electronegative atom will have a slight positive charge.
For example, hydrochloric acid, water, etc are the example of compounds having a polar bond. In hydrochloric acid, the two atoms are hydrogen and chlorine atoms, the electronegativity of chlorine is very high than the electronegativity of hydrogen, so the bond between them is a polar bond.
Water is a compound in which more than one polar bond is present because an oxygen atom has higher electronegativity than a hydrogen atom. Another example of having more than one polar bond is ammonia. Due to these polar bonds only, the polarity is there.

Note:
If the compound is made up of the same elements like ${{O}_{2}}$ then the polarity is not there because there is no difference in the electronegativity, due to which they are known as non-polar compounds.