What are some examples of Bronsted-Lowry bases?
Bases are a type of species that accept a proton.
Bronstead-Lowry bases are species that can accept a proton due to a high energy pair of electrons being present.
Ammonia acts as a base when reacting with water to form a hydroxide ion and an ammonium ion.
In this case, the lone pair on the Nitrogen accepts a hydrogen (proton) from the water molecule hence forming the ammonium ion and acts as a base.
Also, water itself can act as a base when reacting with another water molecule to form a hydroxide ion and a hydronium ion.
One of the lone pairs on Oxygen accepts the proton, once again from the water molecule, and forms the hydronium ion which has a positive charge.
Note: In both examples, the lone pairs were the high energy pair of electrons which allowed the molecule to accept a proton.