International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What is produced when carbon monoxide and water react in an equilibrium reaction?

1. Carbon dioxide and hydrogen

2. Methane and oxygen

3. Hydrogen chloride and ammonia

4. Water and heat

The correct answer is: Carbon dioxide and hydrogen

The reaction between carbon monoxide and water forms carbon dioxide and hydrogen gas. This reaction is classified as a chemical equilibrium process, often referred to as the water-gas shift reaction. In this reaction, carbon monoxide (CO) reacts with water (H₂O) to yield carbon dioxide (CO₂) and hydrogen (H₂). The overall reaction can be represented as follows: CO (g) + H₂O (g) ⇌ CO₂ (g) + H₂ (g) This equilibrium involves a shift in the concentrations of the reactants and products, influenced by changes in conditions such as temperature and pressure. The production of carbon dioxide and hydrogen is significant because hydrogen is a valuable fuel and chemical feedstock, while carbon dioxide can be a product of combustion processes in various applications. The other options do not accurately represent products formed from the reaction of carbon monoxide with water, thus confirming that option A is indeed the correct choice.