Liquid hydrogen which can be chemically denoted as "" is often considered as the significant fuels for rocket.
However rocket in its lower stages uses fuels such as Kerosene and oxygen where as in the higher stages such as second and third stages it uses liquid hydrogen.
Liquid hydrogen is known to easily cool the nozzle and then also other parts of the rocket before mixing with the oxidizer such as the oxygen.
Thus liquid hydrogen helps in preventing nozzle erosion and also reduces combustion chamber.
Liquid hydrogen one the other hand is very expensive as 384,071 gallons of it will cost approximately $376,389.58
.
Thus liquid hydrogen is effectively used as a fuel for rocket.