Answer: Chromium (Cr).
- A Chromium (Cr)
- B Copper
- C Zinc
- D Tin
Correct answer: A. Chromium (Cr)
Explanation: Stainless steel is an alloy of iron with at least 10.5% chromium; the Cr forms a passive oxide layer preventing rust.
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.