Hydrogen is a very promising energy carrier with the highest energy density per unit weight, it is abundantly available, its use as an energy carrier do not release emissions at the point of use, has potential to decarbonize hard-to-abate sectors and provide energy security. Before considering the various aspects of the hydrogen energy value chain, it is essential to understand the chemical, physical, and fuel properties of hydrogen. These properties of hydrogen differ from the other conventional fuels, making it important to familiarize oneself with them when using any hydrogen-based technology.