Here's why:

* Household bleach is typically a diluted solution of sodium hypochlorite (NaClO).

* Sodium hypochlorite, when dissolved in water, produces hypochlorous acid (HOCl) and hydroxide ions (OH-).

* The presence of hydroxide ions (OH-) makes the solution alkaline.

Important Note: While bleach is alkaline, it's crucial to remember that it's a powerful chemical and should be handled with care. Mixing bleach with other cleaning products can produce dangerous fumes.