### Which of the following ions will exhibit colour in aqueous solutions? - `Sc^{3+}` (z = 21) - `La^{3+}` (z = 57) - `Ti^{3+}` (z = 22) - `Lu^{3+}` (z = 71)

The color of ions in aqueous solutions is generally due to d-d transitions of light. This means that ions with partially filled d-orbitals often exhibit color in aqueous solutions.

1. Sc3+ (z = 21): Scandium (Sc) has an atomic number of 21. In its +3 oxidation state, it loses all 3 of its 4s and 3 Knowee AI is a powerful AI-powered study tool designed to help you to solve study problem.