Metals react with oxygen to form:
A. Basic oxides
B. Acidic oxide
C. Both A and B
D. None of the above

Hint: Metals react with oxygen to form their respective metal oxides. This reaction goes in the manner given by the general equation:
\[Metal\text{ }+\text{ }oxygen\xrightarrow{{}}Metal\text{ }oxide\]
To test the acidity or basicity of these metal oxides, they are made to react with water and then tested with litmus paper. A basic solution turns red litmus to blue whereas an acidic solution turns blue litmus to red.

Complete step by step answer:
\[Metal\text{ }oxide\text{ }+\text{ }water\xrightarrow{{}}Metal\text{ }Hydroxides\]
\[MO\text{ }+\text{ }{{H}_{2}}O\xrightarrow{{}}M{{\left( OH \right)}_{2}}\]

Hence this proves that metal oxides are basic in nature. Hence answer option (A) is correct.
Option (C) is not correct because according to established facts, non-metallic oxides are acidic and metallic oxides are basic in nature.
So, the correct answer is “Option A”.

Note: Metal hydroxides are alkaline in nature because they release \[O{{H}^{-}}\] ions in solution on the other hand, non-metallic oxides react with water to form acidic solutions with liberate H+ ions in solution. Therefore, non-metallic oxides would be acidic in nature.
Metallic oxides are basic in nature because they react with dilute acids to form salt and water.
If the metal has more than one valence state, the higher state it is in, the more acidic it’s oxide will be.