Question

Water gas is a mixture of:
(A) Carbon dioxide and hydrogen
(B) Carbon monoxide and hydrogen
(C) Carbon and hydrogen
(D) Ammonia and hydrogen

Answer 1

Due to high bond enthalpy of $\text{H-H}$ bond, ${{\text{H}}_{\text{2}}}$ gas is quite unreactive at room temperature. However at high temperature or in the presence of a catalyst, it combines with many nonmetals and metals to form respective hydride.

Complete answer:
The mixture of Carbon monoxide and hydrogen gas is known as water gas. On a commercial scale it is prepared by the passage of steam over hot coke under very high pressure and temperature. This mixture is also used for the synthesis of methanol and other hydrocarbons hence it is also known as synthesis gas or syngas. Nowadays syngas is produced from sewage, saw-dust, scrap wood and newspaper. The process of production syngas from coal is called coal gasification.
${{\text{C}}_{\text{(S)}}}\text{+}\,{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{(g)}}}\to \text{C}{{\text{O}}_{\text{(g)}}}\text{+}\,{{\text{H}}_{\text{2(g)}}}\text{(Water}\,\text{gas)}$
Water gas is a very important industrial fuel. Carbon monoxide in water gas can undergo further combustion forming carbon dioxide with the liberation of heat.

Additional information:
The production of hydrogen can be increased by reacting carbon monoxide of sin gas mixture with steam in the presence of iron chromate as catalyst.
$\text{C}{{\text{O}}_{\text{(g)}}}\text{+}\,{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{(g)}}}\xrightarrow[Catalyst]{673K}\text{C}{{\text{O}}_{\text{2(g)}}}\text{+}\,{{\text{H}}_{\text{2(g)}}}$
This is called a water gas shift reaction. Carbon dioxide is removed by scrubbing with sodium arsenate solution.
Therefore, option (B) is the correct answer.

Note:
Reaction of steam on hydrocarbons or coke at high temperature in the presence of catalyst yields hydrogen gas.
Industrial hydrogen produced from petrochemical is used as a source of fuel in liquid form as rocket fuel.