Hydrogen has always been one of my favourite elements in the periodic table. So inflammable and energetic that its able to thrust 2000 tons of mass into space and that too in just some seconds. And on the other when it gets combined with oxygen it becomes the source of life. The love of oxygen actually makes hydrogen forget its vivacious past.
Somehow the nature has placed this cruel condition on hydrogen that it must let go its energy in order to be with oxygen forever. Now people all over the world thought that they can actually separate the hydrogen from oxygen and can get all the energy of the hydrogen back. In 1800 William Nicholson finally was able to separate hydrogen from oxygen and they named this process as electrolysis. Now in order to do that, one must give more energy as compared to the energy hydrogen gave in, in order to be with oxygen.
The first law of thermodynamics is the law of nature, which simply means energy will always be conserved. No man in this world can 'create' energy, it can just be transferred from one form to another. The second law of thermodynamics places a condition on how the energy will transfer. It simply says that one can never convert all the energy into work, there will always be some heat losses.
To make a water molecule you need less energy as compared to destroy a water molecule. The nature has placed an interesting principle in these equations, and one can always appreciate this if he/she can realize the importance of water.
One can always come up with an idea of an efficient electrolysis scheme but actually by doing so one will violate the second law of thermodynamics which states, the entropy of the universe is decreasing. There is not a single system in this world in which you put some energy and extract the equal amount of energy back, there always will be heat loses.
The day we will violate the second law of thermodynamics, is the day when a ball fell from a table will be able to go back to its initial position using the same stored potential energy.
I just wish I will be there to see that, but I seriously doubt it.
P.S Readers are encouraged to read about the concept of hydrogen car,
