Answer: Platinum (Pt) and Palladium (Pd).
- A Platinum (Pt) and Palladium (Pd)
- B Iron, valued for its low cost in oxidation catalysis
- C Zinc, commonly used as a sacrificial anode in galvanising
- D Copper, prized for its high electrical conductivity in wiring
Correct answer: A. Platinum (Pt) and Palladium (Pd)
Explanation: Catalytic converters use Pt, Pd, and Rh to oxidise CO and reduce NOx to non-toxic gases.
Aqueous solutions of transition metal ions show characteristic colours caused by electrons absorbing visible light to jump between split d-orbitals; the exact colour depends on the metal, its oxidation state, and surrounding ligands.
Concept context
Transition metals (d-block) and lanthanides/actinides (f-block). Known for coloured compounds, variable oxidation states, complex formation, and catalytic properties. Frequently tested in JEE and NEET.