What type of oxides are formed when non-metals combine with oxygen?

What happens when metal oxide reacts with water?

Which among the following statements is incorrect for magnesium metal?

The metals which are mixed with iron to make stainless steel are:

An element $A$ reacts with water to form a compound $B$ which is used in white washing. The compound $B$ on heating forms an oxide $C$ which on treatment with water gives back $B$. Identify $A$,$B$ and $C$ and give the reactions involved.

Why is sodium kept immersed in kerosene oil?