Which of the given compounds can enhance the efficiency of hydrogen storage tank?

Non-stoichiometric hydrides are formed by

The number of hydrogen molecules possible from its isotopes is

Which compound on electrolysis produces $H_2$ gas at both electrodes?

Metals like $Pt$ and $Pd$ can adsorb large volumes of hydrogen under specific conditions. Such adsorbed hydrogen by the metal is known as:

Calorific value of producer gas is low because of