Q. The aqueous solution containing which one of the following ions will be colourless ? (Atomic no. : Sc = 21, Fe = 26, Ti = 22, Mn = 25)
A) Sc³⁺
B) Fe²⁺
C) Ti³⁺
D) Mn²⁺
Explanation
[Solution from source] Sc³⁺ is 3d⁰, so no d–d transition is possible and its solution is colourless. Ti³⁺ (3d¹), Mn²⁺ (3d⁵) and Fe²⁺ (3d⁶) have unpaired d electrons and are coloured. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.