Question

colour of [Ti(H2O)6]³+ is due to?

Answer 1

$$\begin{gathered} \left[Ti\right(H_{2}O{)}_6{]}^{3+} \\ TheoxidationstateofTiis \\ x+6\left(0\right)=+3 \\ x=+3 \\ T{i}^{22}-3d^{2}4s^2 \\ T{i}^{+3}-3d^1 \\ Sinceithasanunpairedelectronthiscomplexiscoloured. \end{gathered}$$
Due to the transition of this unpaired electron from t_2g to e_g orbital, the energy is absorbed during this process and is emitted in the visible region. Thus the complex is a coloured one.