Question

In the following diagrams, the hydrated proton is shown as a hydronium ion. Water molecules are omitted for clarity. Which of the following diagrams best represents a strong acid, such as HCl, dissolved in water? Check all that apply.

Answer 1

Diagram b best represents a strong acid, such as HCl, dissolved in water.

The best diagram to represent a strong acid is the one on the left (diagram b). This is because strong acids completely dissociate in water, meaning that all of the hydrogen atoms in the acid molecule donate themselves to water molecules to form hydronium ions (
`H_3O^+`).

The hydrogen atoms in strong acids are very weakly bonded to the rest of the molecule, so they are easily donated to water.

The other diagrams do not accurately represent the dissociation of a strong acid. Diagram a shows only a few hydrogen atoms dissociating from the acid molecule.

Diagram c shows the hydrogen atom dissociating from the acid molecule, but it does not show it forming a hydronium ion with a water molecule. Diagram d shows the hydrogen atom dissociating from the acid molecule and forming a hydronium ion, but it also shows the hydrogen atom remaining bonded to the acid molecule.