Why does hydrochloric acid though a covalent compound ionize?

Answer 1

HCl is strictly speaking - a polar covalent molecule with a partial positive charge on hydrogen and a partial negative charge on chlorine. When this is dissolved in water, water too being a polar molecule with a partial positive charge on hydrogen and a partial negative charge on oxygen, hydrogens of HCl are surrounded by oxygens of water forming dipole dipole bonds. So also the chlorines are surrounded by hydrogens of water. When the dipole-dipole bonds are formed, the original bond between H and Cl weakens and ultimately breaks leading to ionization.

Answer 2

Even though hydrochloric acid is a covalent compound, it ionizes in water because the HCl molecule dissociates into H+ and Cl- ions when dissolved in water due to its high polarity. The strong attraction between the partial positive charge on hydrogen and the partial negative charge on chlorine leads to the separation of the ions.