What makes #HCl# a strong acid?
The protonolysis reaction lies strongly to the right.
As an acid, hydrochloric acid undergoes protonolysis in water as shown:
This equilibrium lies strongly, almost quantitatively to the right, and it is the position of this equilibrium that justifies our designation of
O the other hand, for the congeneric hydrogen fluoride:
this equilibrium lies to the LEFT HAND SIDE, and