Name an element which reacts violently with water at room temperature.

What do the following symbols [or formula] denote : 2H ; H₂ ; H⁺. [two atoms, molecule, ion]

When steam is passed over red-hot iron, magnetic oxide of iron and hydrogen are obtained. 'The reaction between steam and red-hot iron is a Reversible Reaction'. What is meant by this statement.

How can you obtain hydrogen from sodium hydroxide [not by electrolysis].