Question

Which of the following represents the water-gas shift reaction?

• A. \(C(s)+H_{2}O(g)\xrightarrow{1270K}CO(g)+H_{2}(g)\)
• B. \(CH_{4}(g)+H_{2}O(g)\xrightarrow[Ni]{1270K}CO(g)+3H_{2}(g)\)
• C. \(CO(g)+H_{2}O(g)\xrightarrow[catalyst]{673K}CO_{2}(g)+H_{2}(g)\)
• D. \(CH_{4}(g)+2O_{2}(g)\rightarrow CO_{2}(g)+2H_{2}O(l)\)

Hint:

Remember: Water gas formation = \(C+H_2O\), Water gas shift = \(CO+H_2O\).

Answer 1

The Correct Option is C

Concept: Water-gas chemistry is an important industrial process used for production of hydrogen and synthesis gas. The water-gas shift reaction specifically refers to reaction in which carbon monoxide reacts with steam to produce carbon dioxide and hydrogen. General reaction: \[ CO+H_2O\rightleftharpoons CO_2+H_2 \] This reaction is extremely important industrially because it increases hydrogen yield after synthesis gas production. It is different from steam reforming reactions and producer gas formation reactions.

Step 1: Analyze Option A carefully. Option A is \[ C+H_2O\rightarrow CO+H_2 \] This is called \[ \text{Water gas formation reaction} \] This produces water gas mixture. Hence not correct.

Step 2: Analyze Option B. Option B is \[ CH_4+H_2O\rightarrow CO+3H_2 \] This reaction is methane steam reforming. It is industrial hydrogen production but not water gas shift reaction. Hence incorrect.

Step 3: Analyze Option C. Option C is \[ CO+H_2O\rightarrow CO_2+H_2 \] This exactly matches the standard water-gas shift reaction. Carbon monoxide gets oxidized to carbon dioxide while water gets reduced to hydrogen gas. Hence this is correct.

Step 4: Analyze Option D. Option D is methane combustion. \[ CH_4+2O_2\rightarrow CO_2+2H_2O \] This is combustion reaction only. Hence incorrect. Thus correct answer is \[ \boxed{CO+H_2O\rightarrow CO_2+H_2} \]