[Image of a beaker of water with dissolved HCl molecules]

Description:

When a strong acid like HCl is dissolved in water, it completely dissociates into its constituent ions, H+ and Cl-. The H+ ions are free to move around in the solution, while the Cl- ions are associated with water molecules. This results in a high concentration of H+ ions in the solution, which makes it acidic.

The following equation shows the dissociation of HCl in water:

```

HCl(aq) -> H+(aq) + Cl-(aq)

```