The formula of Nickel (ll) oxide is NiO.
2Ni(s) + O2(g) ----> 2NiO(s)
It is in solid state. It contains one atom of Nickel and one atom of Oxygen. It is a green coloured powder. It is basic in nature because it is a metal oxide. As we know that metal oxides are basic in nature.
NiO(s) + H2O (l) ---> Ni(OH)2
It's solution turns red litmus paper into blue which proves that it is a base.
