Question

 [Ti(H2O)6]+3 is coloured while [Sc(H2O)6] is coloured GiVe reason

Answer 1

In [Ti(H2O)6]+3 complex, d-d transition takes place between t and e of d-subshell. The electron get excited to higher energy level when exposed to high energy. When electron returns to its ground state, it emits energy of particular wavelength, due which element shows colour.
Sc has the electronic configuration [Ar}3d1 . Since it is present in the complex as Sc3+ it has no unpaired electron. It will also undergo d2sp3 hybridization to accomodate 6 pairs of electrons from water.So it is also octahedral, colourless and diamagnetic due to absence of unpaired electron.