Basic principle of hydrogen economy is transportation and storage of energy in the form of liquid or gaseous hydrogen. Which property of hydrogen may be useful for this purpose? Support your answer with the chemical equation if required.
Hydrogen is in gaseous form at room temperature and due to the bulk and leakage factors, it is difficult to transport it. So, if pressure is applied and cooling is done then the gaseous hydrogen can be converted to liquid form.
Being liquid, less consumption of volume takes place, so transportation can be done easily. Thus, the basic property of hydrogen which is useful for hydrogen economy is that it can be converted into a liquid - by cooling under high pressure.