Answer: Mn 2+.
- A Ti<sup>3+</sup>
- B Mn<sup>2+</sup>
- C Cr<sup>3+</sup>
- D V<sup>3+</sup>
Correct answer: B. Mn<sup>2+</sup>
Explanation: Mn<sup>2+</sup> is d<sup>5</sup> with 5 unpaired electrons (5.92 BM), more than Ti<sup>3+</sup> (d<sup>1</sup>), V<sup>3+</sup> (d<sup>2</sup>) or Cr<sup>3+</sup> (d<sup>3</sup>).
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.