Here's why:

* Dissociation: When a base dissolves in water, it releases hydroxide ions (OH-) into the solution.

* Strong bases: These bases ionize completely in solution, meaning all of the base molecules break apart into ions. This leads to a high concentration of OH- ions, making the solution highly alkaline (basic).

Examples of strong bases:

* Group 1 hydroxides (LiOH, NaOH, KOH, RbOH, CsOH)

* Group 2 hydroxides (Ca(OH)2, Sr(OH)2, Ba(OH)2)

Important Note: While most strong bases are metal hydroxides, some non-metal containing compounds can also be strong bases, like the amide ion (NH2-)

Contrast with weak bases:

* Weak bases only partially dissociate in solution. They establish an equilibrium between the undissociated base molecules and the ions they form. This results in a lower concentration of OH- ions compared to strong bases, making the solution less alkaline.

Examples of weak bases:

* Ammonia (NH3)

* Many organic amines

Let me know if you have any more questions!