Which salts are formed when sulfuric acid reacts with metals?

An alkali metal $A$ gives a compound $B$ (molecular mass $= 40$) on reacting with water. The compound $B$ gives a soluble compound $C$ on treatment with aluminium oxide. Identify $A$,$B$ and $C$ and give the reaction involved.

Which of the following represents the correct order of reactivity of metals?

Why does a magnesium ribbon start floating when it is placed in hot water?

Which non-metal element is used in the vulcanization of rubber?

Stainless steel is a very useful material in our daily life. In stainless steel,iron is mixed with: