Identify the complexes which are expected to be coloured. Give explanation.

Step-by-step solution

2. (A) In [ Ti ( NO ₃ )₄ ], O . N . of Ti is +4 . Hence, in Ti (IV) (1 s^2, 2 s^2, 2 p^6, 3 s^2, 3 p^6 ) incomplete d -orbital is not present. So, it is colourless. (B) In [ Cu ( NCCH ₃ ) ]⁺ BF ₄, O . N. of Cu is +1 . Hence, in Cu ( I ) [1 ~s ^2, 2 ~s ^2, 2 p ^6, 3 ~s ^2, 3 p ^6, 3 ~d ¹⁰ ] incomplete d-orbital is not present. So it is also colourless. (C) In [ Cr ( NH ₃ )₆ ]³⁺ 3 Cl , O.N. of Cr is +3 . Hence, in Cr (III) (1 ~s ^2, 2 ~s ^2 2 p ^6, 3 ~s ^2, 3 p ^6, 3 ~d ^3 ) incomplete d - orbitals are present. So, i