Why is HCI(g) capable of being dissolved in water?

1 Answer
Dec 29, 2016

The polarity of HCl and the fact that it results in a strong acid both play a role in accounting for the solubility.


There are two factors that contribute to the solubility of HCl in water.

First, there is a considerable difference in electronegativity between the two elements, which causes the HCl molecule (like water itself) to be polar.

The dipole on the solute #HCl# and the solvent #H_2O# allow the two to interact strongly. This interaction is a crucial part of the mixing that produces the solution.

Secondly, HCl (aq) is a strong acid, which means it ionizes to a very high degree (essentially 100%) in the presence of water. The H atom is removed as a hydrogen ion, #H^+#, which is then bonded to the oxygen atom in the water molecule, resulting in a hydronium ion #H3O^+#. So, this existence of ions further aids in the solubility.