Bleach will kill mosquito larvae and pupa, but it is not recommended that you add bleach directly to standing water sources that foster mosquitoes.
This is because bleach is toxic to all types of life, and is a powerful and hazardous chemical that you do not want to release into the environment.
Not only will it kill the mosquitoes, but the bleach will also kill bacteria and fungi, and also poison fish, birds, and any mammals that use that water as a source of hydration.