Answer:
The oxides of the Group I and Group II elements react with water to form strongly basic solutions contains hydroxide anion, OH–.
Basic oxide:
Metals react with oxygen to give basic compounds of oxygen. These compounds are usually ionic in nature. Group 1, 2 and lanthanides form basic compounds of oxygen when they react with dioxygen. During the formation of these compounds, a large amount of energy is released. These compounds readily react with water except a few exceptions.
Examples: M2O3, MO2, ThO2