Which of the following reactions increases the production of...

The process of producing syn gas or synthesis gas from coal is called 'coal gasification'.

$\mathop{C\left(s\right)}_{Coal} + \mathop{{H}_{2}O\left(g\right)}_{Steam}\mathop{\to}_{Ni}^{1270K}\mathop{\mathop{CO\left(g\right) + {H}_{2}\left(g\right)}_{⏟}}_{Synthesis gas}$

The production of hydrogen can be increased by reacting carbon monoxide of the syn gas with steam in the presence of iron chromate as a catalyst at $673K$.

$CO\left(g\right) + {H}_{2}O\left(g\right)\overset{{FeCrO}_{4}, 673K}{⟶}{CO}_{2}\left(g\right) + {H}_{2}\left(g\right)$

${CO}_{2}$ is removed by scrubbing with a solution of sodium arsenite.