Identify the metal which is NOT used in catalytic converters.

The correct answer is Option (1) → Gold

Option (1) Gold — Not used in catalytic converters. NCERT names only platinum–palladium and rhodium as the catalysts.

Option (2) Platinum — Used in catalytic converters.

Option (3) Rhodium — Used in catalytic converters.

Option (4) Palladium — Used in catalytic converters. These metals turn unburnt hydrocarbons into CO₂ and water.

Note: This question is from Chapter 16, Environmental Issues, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.

NCERT Extract (Pre-rationalised edition, Chapter 16, Environmental Issues):
Air Pollution and Its Control – “… Automobiles are a major cause for atmospheric pollution atleast in the metro cities. As the number of vehicles increase on the streets, this problem is now shifting to the other cities too. Proper maintenance of automobiles along with use of lead-free petrol or diesel can reduce the pollutants they emit. Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases.”