Question

Water gas is produced by:
A. Passing steam over red hot coke
B. Passing steam and air over red hot coke
C. Burning coke in excess of air
D. Burning coke in limited supply of air

Answer 1

Hint: We know that water gas is described as a mixture of hydrogen and carbon monoxide that is $\left( {CO + {H_2}} \right)$. It is obtained from syngas or synthesis gas, which is described as a fuel gas. It mainly contains carbon monoxide, hydrogen and sometimes carbon dioxide.

Complete step by step answer:
The water-gas shift reaction is used for the description of the reaction that occurs between water vapor and carbon monoxide to produce carbon dioxide and hydrogen. The reaction is shown below.
$CO + {H_2}O \to C{O_2} + {H_2}$
Further, it is possible to use the water-gas shift reaction to oxidize the carbon monoxide while creating additional hydrogen.
So we conclude that water gas is a fuel. It is made by passing steam over red hot coke (red-hot carbon fuel). The reaction is shown below.
${H_2}O\left( g \right) + C\left( s \right) \to CO\left( g \right) + {H_2}\left( g \right)\left( {\Delta H = 131\;kJ/mol} \right)$
This reaction is found to be endothermic in nature, thus, the fuel must then be reheated continuously to keep the reaction going.
Hence, we can say that water gas is produced by passing steam over red hot coke.
Thus, the correct option is A.

Note:
We can do the production of pure hydrogen from water gas with the help of water-gas shift reaction. This should be achieved when we subsequently remove the resulting carbon dioxide when carbon monoxide undergoes reaction with water.