The highest industrial consumption of molecular hydrogen is to produce compounds of element ...... .

Which of the following reactions produces hydrogen?

How can the production of hydrogen from water gas be increased by using the water gas shift reaction?

The reaction of $H_2S$ with $O_2$ produces .....

Identify the catalyst used to transform carbon monoxide from water gas into carbon dioxide.

What do you understand by $(i)$ electron deficient,$(ii)$ electron precise,and $(iii)$ electron rich compounds of hydrogen? Provide justification with suitable examples.