JEE Main 2023 — Hydrogen Question with Solution

These reactions are part of the water-gas shift reaction used in the industrial production of hydrogen. The first reaction is the endothermic steam reforming of coal (carbon), while the second reaction is the exothermic water-gas shift reaction.

1. Carbon reacts with steam at high temperatures (around 1000°C or 1273 K) to form carbon monoxide and hydrogen:
   
   C(s) + H${}_2$O(g) $\underset{T_1}{\to }$ CO(g) + H${}_2$(g)




2. Then carbon monoxide reacts with steam in the presence of a catalyst to produce carbon dioxide and more hydrogen:
   
   CO(g) + H${}_2$O(g) $\underset{Catalyst}{\overset{[T_2]}{\to }}$ CO${}_2$(g) + H${}_2$(g)

Since the first reaction is endothermic (absorbs heat), it requires a higher temperature to proceed than the second reaction, which is exothermic (releases heat). Therefore, the temperature T${}_1$ should be higher than T${}_2$.