The most abundant element in the universe is

Hydrogen can be prepared by mixing steam and water gas at $500 \, ^oC$ in the presence of $Fe_3O_4$ and $Cr_2O_3$ as catalysts. This process is called:

Which of the following pairs of reactions give $H_2$ gas as a product upon hydrolysis?

The difference between heat of adsorption of ortho and para hydrogen is $......... \ kJ \ mol^{-1}$.

If a mole of $H_2$ molecules is heated to a high temperature,which of the following reactions takes place?

Hydrogen directly combines with