Catalytic Converter Reactions Steps:

• Identify key pollutants removed: carbon monoxide (CO), unburnt hydrocarbons, and oxides of nitrogen (NOx).
• Recall reactions: CO oxidized to CO2; hydrocarbons oxidized to CO2 and H2O; NOx reduced to N2 and O2.
• Compare each option to these reactions for accuracy in pollutant and process.
• Select the option that best matches a valid removal process despite minor wording issues.

Why A is correct:

• Carbon monoxide is oxidized by the catalyst to carbon dioxide (2CO + O2 → 2CO2), removing the toxic pollutant CO.

Why the others are wrong:

• B: NOx are reduced to N2 and O2 (2NO → N2 + O2), not oxidized to nitric acid (HNO3).
• C: Unburnt hydrocarbons are oxidized to CO2 and water (H2O), not hydrogen gas.
• D: Identical to C, so also incorrect on the product.

Final answer: A